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diff --git a/doc/rrdcreate.txt b/doc/rrdcreate.txt
index 627e92d57ad757696a7af8418d703c246109d939..0a82202f8b90692bf854440a7060c4d20af65456 100644 (file)
--- a/doc/rrdcreate.txt
+++ b/doc/rrdcreate.txt
(R\bRR\bRD\bD) files. The file is created at its final, full size and filled
with _\b*_\bU_\bN_\bK_\bN_\bO_\bW_\bN_\b* data.
- _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
-
+ _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
The name of the R\bRR\bRD\bD you want to create. R\bRR\bRD\bD files should end with the
extension _\b._\br_\br_\bd. However, R\bRR\bRD\bDt\bto\boo\bol\bl will accept any filename.
- -\b--\b-s\bst\bta\bar\brt\bt|\b|-\b-b\bb _\bs_\bt_\ba_\br_\bt _\bt_\bi_\bm_\be (\b(d\bde\bef\bfa\bau\bul\blt\bt:\b: n\bno\bow\bw -\b- 1\b10\b0s\bs)\b)
-
+ -\b--\b-s\bst\bta\bar\brt\bt|\b|-\b-b\bb _\bs_\bt_\ba_\br_\bt _\bt_\bi_\bm_\be (\b(d\bde\bef\bfa\bau\bul\blt\bt:\b: n\bno\bow\bw -\b- 1\b10\b0s\bs)\b)
Specifies the time in seconds since 1970-01-01 UTC when the first value
should be added to the R\bRR\bRD\bD. R\bRR\bRD\bDt\bto\boo\bol\bl will not accept any data timed
before or at the time specified.
- See also AT-STYLE TIME SPECIFICATION section in the _\br_\br_\bd_\bf_\be_\bt_\bc_\bh documenta-
- tion for other ways to specify time.
-
- -\b--\b-s\bst\bte\bep\bp|\b|-\b-s\bs _\bs_\bt_\be_\bp (\b(d\bde\bef\bfa\bau\bul\blt\bt:\b: 3\b30\b00\b0 s\bse\bec\bco\bon\bnd\bds\bs)\b)
+ See also AT-STYLE TIME SPECIFICATION section in the _\br_\br_\bd_\bf_\be_\bt_\bc_\bh
+ documentation for other ways to specify time.
+ -\b--\b-s\bst\bte\bep\bp|\b|-\b-s\bs _\bs_\bt_\be_\bp (\b(d\bde\bef\bfa\bau\bul\blt\bt:\b: 3\b30\b00\b0 s\bse\bec\bco\bon\bnd\bds\bs)\b)
Specifies the base interval in seconds with which data will be fed into
the R\bRR\bRD\bD.
- D\bDS\bS:\b:_\bd_\bs_\b-_\bn_\ba_\bm_\be:\b:_\bD_\bS_\bT:\b:_\bd_\bs_\bt _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
-
- A single R\bRR\bRD\bD can accept input from several data sources (D\bDS\bS), for exam-
- ple incoming and outgoing traffic on a specific communication line.
+ D\bDS\bS:\b:_\bd_\bs_\b-_\bn_\ba_\bm_\be:\b:_\bD_\bS_\bT:\b:_\bd_\bs_\bt _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
+ A single R\bRR\bRD\bD can accept input from several data sources (D\bDS\bS), for
+ example incoming and outgoing traffic on a specific communication line.
With the D\bDS\bS configuration option you must define some basic properties
of each data source you want to store in the R\bRR\bRD\bD.
D\bDS\bS:\b:_\bd_\bs_\b-_\bn_\ba_\bm_\be:\b:_\bC_\bO_\bM_\bP_\bU_\bT_\bE:\b:_\br_\bp_\bn_\b-_\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn
- In order to decide which data source type to use, review the defini-
- tions that follow. Also consult the section on "HOW TO MEASURE" for
- further insight.
+ In order to decide which data source type to use, review the
+ definitions that follow. Also consult the section on "HOW TO MEASURE"
+ for further insight.
G\bGA\bAU\bUG\bGE\bE
is for things like temperatures or number of people in a room or
as "Unknown", but can mistake some counter resets for a legitimate
counter wrap.
- For a 5 minute step and 32-bit counter, the probability of mistak-
- ing a counter reset for a legitimate wrap is arguably about 0.8%
- per 1Mbps of maximum bandwidth. Note that this equates to 80% for
- 100Mbps interfaces, so for high bandwidth interfaces and a 32bit
- counter, DERIVE with min=0 is probably preferable. If you are using
- a 64bit counter, just about any max setting will eliminate the pos-
- sibility of mistaking a reset for a counter wrap.
+ For a 5 minute step and 32-bit counter, the probability of
+ mistaking a counter reset for a legitimate wrap is arguably about
+ 0.8% per 1Mbps of maximum bandwidth. Note that this equates to 80%
+ for 100Mbps interfaces, so for high bandwidth interfaces and a
+ 32bit counter, DERIVE with min=0 is probably preferable. If you are
+ using a 64bit counter, just about any max setting will eliminate
+ the possibility of mistaking a reset for a counter wrap.
A\bAB\bBS\bSO\bOL\bLU\bUT\bTE\bE
is for counters which get reset upon reading. This is used for fast
- counters which tend to overflow. So instead of reading them nor-
- mally you reset them after every read to make sure you have a maxi-
- mum time available before the next overflow. Another usage is for
- things you count like number of messages since the last update.
+ counters which tend to overflow. So instead of reading them
+ normally you reset them after every read to make sure you have a
+ maximum time available before the next overflow. Another usage is
+ for things you count like number of messages since the last update.
C\bCO\bOM\bMP\bPU\bUT\bTE\bE
is for storing the result of a formula applied to other data
sources in the R\bRR\bRD\bD. This data source is not supplied a value on
update, but rather its Primary Data Points (PDPs) are computed from
the PDPs of the data sources according to the rpn-expression that
- defines the formula. Consolidation functions are then applied nor-
- mally to the PDPs of the COMPUTE data source (that is the rpn-
+ defines the formula. Consolidation functions are then applied
+ normally to the PDPs of the COMPUTE data source (that is the rpn-
expression is only applied to generate PDPs). In database software,
such data sets are referred to as "virtual" or "computed" columns.
_\br_\bp_\bn_\b-_\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn defines the formula used to compute the PDPs of a
COMPUTE data source from other data sources in the same <RRD>. It is
similar to defining a C\bCD\bDE\bEF\bF argument for the graph command. Please refer
- to that manual page for a list and description of RPN operations sup-
- ported. For COMPUTE data sources, the following RPN operations are not
- supported: COUNT, PREV, TIME, and LTIME. In addition, in defining the
- RPN expression, the COMPUTE data source may only refer to the names of
- data source listed previously in the create command. This is similar to
- the restriction that C\bCD\bDE\bEF\bFs must refer only to D\bDE\bEF\bFs and C\bCD\bDE\bEF\bFs previously
- defined in the same graph command.
-
- R\bRR\bRA\bA:\b:_\bC_\bF:\b:_\bc_\bf _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
-
+ to that manual page for a list and description of RPN operations
+ supported. For COMPUTE data sources, the following RPN operations are
+ not supported: COUNT, PREV, TIME, and LTIME. In addition, in defining
+ the RPN expression, the COMPUTE data source may only refer to the names
+ of data source listed previously in the create command. This is similar
+ to the restriction that C\bCD\bDE\bEF\bFs must refer only to D\bDE\bEF\bFs and C\bCD\bDE\bEF\bFs
+ previously defined in the same graph command.
+
+ R\bRR\bRA\bA:\b:_\bC_\bF:\b:_\bc_\bf _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
The purpose of an R\bRR\bRD\bD is to store data in the round robin archives
(R\bRR\bRA\bA). An archive consists of a number of data values or statistics for
each of the defined data-sources (D\bDS\bS) and is defined with an R\bRR\bRA\bA line.
Note that data aggregation inevitably leads to loss of precision and
information. The trick is to pick the aggregate function such that the
- _\bi_\bn_\bt_\be_\br_\be_\bs_\bt_\bi_\bn_\bg properties of your data is kept across the aggregation pro-
- cess.
+ _\bi_\bn_\bt_\be_\br_\be_\bs_\bt_\bi_\bn_\bg properties of your data is kept across the aggregation
+ process.
The format of R\bRR\bRA\bA line for these consolidation functions is:
@@ -197,11 +192,11 @@ A\bAb\bbe\ber\brr\bra\ban\bnt\bt B\bBe\beh\bha\bav\bvi\bio\bor\br D\bDe\bet\bte\bec\bct\bti\bio\bon\bn w\b
· R\bRR\bRA\bA:\b:_\bM_\bH_\bW_\bP_\bR_\bE_\bD_\bI_\bC_\bT:\b:_\br_\bo_\bw_\bs:\b:_\ba_\bl_\bp_\bh_\ba:\b:_\bb_\be_\bt_\ba:\b:_\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd[:\b:_\br_\br_\ba_\b-_\bn_\bu_\bm]
- · R\bRR\bRA\bA:\b:_\bS_\bE_\bA_\bS_\bO_\bN_\bA_\bL:\b:_\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd:\b:_\bg_\ba_\bm_\bm_\ba:\b:_\br_\br_\ba_\b-_\bn_\bu_\bm[:\b:s\bsm\bmo\boo\bot\bth\bhi\bin\bng\bg-\b-w\bwi\bin\bnd\bdo\bow\bw=\b=_\bf_\br_\ba_\bc_\b-
- _\bt_\bi_\bo_\bn]
+ · R\bRR\bRA\bA:\b:_\bS_\bE_\bA_\bS_\bO_\bN_\bA_\bL:\b:_\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd:\b:_\bg_\ba_\bm_\bm_\ba:\b:_\br_\br_\ba_\b-
+ _\bn_\bu_\bm[:\b:s\bsm\bmo\boo\bot\bth\bhi\bin\bng\bg-\b-w\bwi\bin\bnd\bdo\bow\bw=\b=_\bf_\br_\ba_\bc_\bt_\bi_\bo_\bn]
- · R\bRR\bRA\bA:\b:_\bD_\bE_\bV_\bS_\bE_\bA_\bS_\bO_\bN_\bA_\bL:\b:_\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd:\b:_\bg_\ba_\bm_\bm_\ba:\b:_\br_\br_\ba_\b-_\bn_\bu_\bm[:\b:s\bsm\bmo\boo\bot\bth\bhi\bin\bng\bg-\b-w\bwi\bin\bn-\b-
- d\bdo\bow\bw=\b=_\bf_\br_\ba_\bc_\bt_\bi_\bo_\bn]
+ · R\bRR\bRA\bA:\b:_\bD_\bE_\bV_\bS_\bE_\bA_\bS_\bO_\bN_\bA_\bL:\b:_\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd:\b:_\bg_\ba_\bm_\bm_\ba:\b:_\br_\br_\ba_\b-
+ _\bn_\bu_\bm[:\b:s\bsm\bmo\boo\bot\bth\bhi\bin\bng\bg-\b-w\bwi\bin\bnd\bdo\bow\bw=\b=_\bf_\br_\ba_\bc_\bt_\bi_\bo_\bn]
· R\bRR\bRA\bA:\b:_\bD_\bE_\bV_\bP_\bR_\bE_\bD_\bI_\bC_\bT:\b:_\br_\bo_\bw_\bs:\b:_\br_\br_\ba_\b-_\bn_\bu_\bm
@@ -211,25 +206,25 @@ A\bAb\bbe\ber\brr\bra\ban\bnt\bt B\bBe\beh\bha\bav\bvi\bio\bor\br D\bDe\bet\bte\bec\bct\bti\bio\bon\bn w\b
ways. First, each of the R\bRR\bRA\bAs is updated once for every primary data
point. Second, these R\bRR\bRA\bAs\bs are interdependent. To generate real-time
confidence bounds, a matched set of SEASONAL, DEVSEASONAL, DEVPREDICT,
- and either HWPREDICT or MHWPREDICT must exist. Generating smoothed val-
- ues of the primary data points requires a SEASONAL R\bRR\bRA\bA and either an
- HWPREDICT or MHWPREDICT R\bRR\bRA\bA. Aberrant behavior detection requires FAIL-
- URES, DEVSEASONAL, SEASONAL, and either HWPREDICT or MHWPREDICT.
+ and either HWPREDICT or MHWPREDICT must exist. Generating smoothed
+ values of the primary data points requires a SEASONAL R\bRR\bRA\bA and either an
+ HWPREDICT or MHWPREDICT R\bRR\bRA\bA. Aberrant behavior detection requires
+ FAILURES, DEVSEASONAL, SEASONAL, and either HWPREDICT or MHWPREDICT.
- The predicted, or smoothed, values are stored in the HWPREDICT or MHW-
- PREDICT R\bRR\bRA\bA. HWPREDICT and MHWPREDICT are actually two variations on
+ The predicted, or smoothed, values are stored in the HWPREDICT or
+ MHWPREDICT R\bRR\bRA\bA. HWPREDICT and MHWPREDICT are actually two variations on
the Holt-Winters method. They are interchangeable. Both attempt to
- decompose data into three components: a baseline, a trend, and a sea-
- sonal coefficient. HWPREDICT adds its seasonal coefficient to the
- baseline to form a prediction, whereas MHWPREDICT multiplies its sea-
- sonal coefficient by the baseline to form a prediction. The difference
- is noticeable when the baseline changes significantly in the course of
- a season; HWPREDICT will predict the seasonality to stay constant as
- the baseline changes, but MHWPREDICT will predict the seasonality to
- grow or shrink in proportion to the baseline. The proper choice of
- method depends on the thing being modeled. For simplicity, the rest of
- this discussion will refer to HWPREDICT, but MHWPREDICT may be substi-
- tuted in its place.
+ decompose data into three components: a baseline, a trend, and a
+ seasonal coefficient. HWPREDICT adds its seasonal coefficient to the
+ baseline to form a prediction, whereas MHWPREDICT multiplies its
+ seasonal coefficient by the baseline to form a prediction. The
+ difference is noticeable when the baseline changes significantly in the
+ course of a season; HWPREDICT will predict the seasonality to stay
+ constant as the baseline changes, but MHWPREDICT will predict the
+ seasonality to grow or shrink in proportion to the baseline. The proper
+ choice of method depends on the thing being modeled. For simplicity,
+ the rest of this discussion will refer to HWPREDICT, but MHWPREDICT may
+ be substituted in its place.
The predicted deviations are stored in DEVPREDICT (think a standard
deviation which can be scaled to yield a confidence band). The FAILURES
@@ -243,8 +238,8 @@ A\bAb\bbe\ber\brr\bra\ban\bnt\bt B\bBe\beh\bha\bav\bvi\bio\bor\br D\bDe\bet\bte\bec\bct\bti\bio\bon\bn w\b
the Holt-Winters forecasting algorithm and the seasonal deviations,
respectively. There is one entry per observation time point in the
seasonal cycle. For example, if primary data points are generated every
- five minutes and the seasonal cycle is 1 day, both SEASONAL and DEVSEA-
- SONAL will have 288 rows.
+ five minutes and the seasonal cycle is 1 day, both SEASONAL and
+ DEVSEASONAL will have 288 rows.
In order to simplify the creation for the novice user, in addition to
supporting explicit creation of the HWPREDICT, SEASONAL, DEVPREDICT,
@@ -257,46 +252,46 @@ A\bAb\bbe\ber\brr\bra\ban\bnt\bt B\bBe\beh\bha\bav\bvi\bio\bor\br D\bDe\bet\bte\bec\bct\bti\bio\bon\bn w\b
and entries in these RRAs. For the HWPREDICT CF, _\br_\bo_\bw_\bs should be larger
than the _\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd. If the DEVPREDICT R\bRR\bRA\bA is implicitly created,
the default number of rows is the same as the HWPREDICT _\br_\bo_\bw_\bs argument.
- If the FAILURES R\bRR\bRA\bA is implicitly created, _\br_\bo_\bw_\bs will be set to the _\bs_\be_\ba_\b-
- _\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd argument of the HWPREDICT R\bRR\bRA\bA. Of course, the R\bRR\bRD\bDt\bto\boo\bol\bl
+ If the FAILURES R\bRR\bRA\bA is implicitly created, _\br_\bo_\bw_\bs will be set to the
+ _\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd argument of the HWPREDICT R\bRR\bRA\bA. Of course, the R\bRR\bRD\bDt\bto\boo\bol\bl
_\br_\be_\bs_\bi_\bz_\be command is available if these defaults are not sufficient and
the creator wishes to avoid explicit creations of the other specialized
function R\bRR\bRA\bAs\bs.
- _\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd specifies the number of primary data points in a sea-
- sonal cycle. If SEASONAL and DEVSEASONAL are implicitly created, this
- argument for those R\bRR\bRA\bAs\bs is set automatically to the value specified by
- HWPREDICT. If they are explicitly created, the creator should verify
- that all three _\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd arguments agree.
-
- _\ba_\bl_\bp_\bh_\ba is the adaption parameter of the intercept (or baseline) coeffi-
- cient in the Holt-Winters forecasting algorithm. See rrdtool for a
- description of this algorithm. _\ba_\bl_\bp_\bh_\ba must lie between 0 and 1. A value
- closer to 1 means that more recent observations carry greater weight in
- predicting the baseline component of the forecast. A value closer to 0
- means that past history carries greater weight in predicting the base-
- line component.
-
- _\bb_\be_\bt_\ba is the adaption parameter of the slope (or linear trend) coeffi-
- cient in the Holt-Winters forecasting algorithm. _\bb_\be_\bt_\ba must lie between
- 0 and 1 and plays the same role as _\ba_\bl_\bp_\bh_\ba with respect to the predicted
- linear trend.
+ _\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd specifies the number of primary data points in a
+ seasonal cycle. If SEASONAL and DEVSEASONAL are implicitly created,
+ this argument for those R\bRR\bRA\bAs\bs is set automatically to the value
+ specified by HWPREDICT. If they are explicitly created, the creator
+ should verify that all three _\bs_\be_\ba_\bs_\bo_\bn_\ba_\bl _\bp_\be_\br_\bi_\bo_\bd arguments agree.
+
+ _\ba_\bl_\bp_\bh_\ba is the adaption parameter of the intercept (or baseline)
+ coefficient in the Holt-Winters forecasting algorithm. See rrdtool for
+ a description of this algorithm. _\ba_\bl_\bp_\bh_\ba must lie between 0 and 1. A
+ value closer to 1 means that more recent observations carry greater
+ weight in predicting the baseline component of the forecast. A value
+ closer to 0 means that past history carries greater weight in
+ predicting the baseline component.
+
+ _\bb_\be_\bt_\ba is the adaption parameter of the slope (or linear trend)
+ coefficient in the Holt-Winters forecasting algorithm. _\bb_\be_\bt_\ba must lie
+ between 0 and 1 and plays the same role as _\ba_\bl_\bp_\bh_\ba with respect to the
+ predicted linear trend.
_\bg_\ba_\bm_\bm_\ba is the adaption parameter of the seasonal coefficients in the
- Holt-Winters forecasting algorithm (HWPREDICT) or the adaption parame-
- ter in the exponential smoothing update of the seasonal deviations. It
- must lie between 0 and 1. If the SEASONAL and DEVSEASONAL R\bRR\bRA\bAs\bs are cre-
- ated implicitly, they will both have the same value for _\bg_\ba_\bm_\bm_\ba: the
- value specified for the HWPREDICT _\ba_\bl_\bp_\bh_\ba argument. Note that because
- there is one seasonal coefficient (or deviation) for each time point
- during the seasonal cycle, the adaptation rate is much slower than the
- baseline. Each seasonal coefficient is only updated (or adapts) when
- the observed value occurs at the offset in the seasonal cycle corre-
- sponding to that coefficient.
+ Holt-Winters forecasting algorithm (HWPREDICT) or the adaption
+ parameter in the exponential smoothing update of the seasonal
+ deviations. It must lie between 0 and 1. If the SEASONAL and
+ DEVSEASONAL R\bRR\bRA\bAs\bs are created implicitly, they will both have the same
+ value for _\bg_\ba_\bm_\bm_\ba: the value specified for the HWPREDICT _\ba_\bl_\bp_\bh_\ba argument.
+ Note that because there is one seasonal coefficient (or deviation) for
+ each time point during the seasonal cycle, the adaptation rate is much
+ slower than the baseline. Each seasonal coefficient is only updated (or
+ adapts) when the observed value occurs at the offset in the seasonal
+ cycle corresponding to that coefficient.
If SEASONAL and DEVSEASONAL R\bRR\bRA\bAs\bs are created explicitly, _\bg_\ba_\bm_\bm_\ba need not
- be the same for both. Note that _\bg_\ba_\bm_\bm_\ba can also be changed via the R\bRR\bRD\bD-\b-
- t\bto\boo\bol\bl _\bt_\bu_\bn_\be command.
+ be the same for both. Note that _\bg_\ba_\bm_\bm_\ba can also be changed via the
+ R\bRR\bRD\bDt\bto\boo\bol\bl _\bt_\bu_\bn_\be command.
_\bs_\bm_\bo_\bo_\bt_\bh_\bi_\bn_\bg_\b-_\bw_\bi_\bn_\bd_\bo_\bw specifies the fraction of a season that should be
averaged around each point. By default, the value of _\bs_\bm_\bo_\bo_\bt_\bh_\bi_\bn_\bg_\b-_\bw_\bi_\bn_\bd_\bo_\bw
@@ -305,14 +300,15 @@ A\bAb\bbe\ber\brr\bra\ban\bnt\bt B\bBe\beh\bha\bav\bvi\bio\bor\br D\bDe\bet\bte\bec\bct\bti\bio\bon\bn w\b
nearest neighbors. Setting _\bs_\bm_\bo_\bo_\bt_\bh_\bi_\bn_\bg_\b-_\bw_\bi_\bn_\bd_\bo_\bw to zero will disable the
running-average smoother altogether.
- _\br_\br_\ba_\b-_\bn_\bu_\bm provides the links between related R\bRR\bRA\bAs\bs. If HWPREDICT is speci-
- fied alone and the other R\bRR\bRA\bAs\bs are created implicitly, then there is no
- need to worry about this argument. If R\bRR\bRA\bAs\bs are created explicitly, then
- carefully pay attention to this argument. For each R\bRR\bRA\bA which includes
- this argument, there is a dependency between that R\bRR\bRA\bA and another R\bRR\bRA\bA.
- The _\br_\br_\ba_\b-_\bn_\bu_\bm argument is the 1-based index in the order of R\bRR\bRA\bA creation
- (that is, the order they appear in the _\bc_\br_\be_\ba_\bt_\be command). The dependent
- R\bRR\bRA\bA for each R\bRR\bRA\bA requiring the _\br_\br_\ba_\b-_\bn_\bu_\bm argument is listed here:
+ _\br_\br_\ba_\b-_\bn_\bu_\bm provides the links between related R\bRR\bRA\bAs\bs. If HWPREDICT is
+ specified alone and the other R\bRR\bRA\bAs\bs are created implicitly, then there
+ is no need to worry about this argument. If R\bRR\bRA\bAs\bs are created
+ explicitly, then carefully pay attention to this argument. For each R\bRR\bRA\bA
+ which includes this argument, there is a dependency between that R\bRR\bRA\bA
+ and another R\bRR\bRA\bA. The _\br_\br_\ba_\b-_\bn_\bu_\bm argument is the 1-based index in the order
+ of R\bRR\bRA\bA creation (that is, the order they appear in the _\bc_\br_\be_\ba_\bt_\be command).
+ The dependent R\bRR\bRA\bA for each R\bRR\bRA\bA requiring the _\br_\br_\ba_\b-_\bn_\bu_\bm argument is listed
+ here:
· HWPREDICT _\br_\br_\ba_\b-_\bn_\bu_\bm is the index of the SEASONAL R\bRR\bRA\bA.
@@ -330,9 +326,9 @@ A\bAb\bbe\ber\brr\bra\ban\bnt\bt B\bBe\beh\bha\bav\bvi\bio\bor\br D\bDe\bet\bte\bec\bct\bti\bio\bon\bn w\b
_\bw_\bi_\bn_\bd_\bo_\bw _\bl_\be_\bn_\bg_\bt_\bh is the number of time points in the window. Specify an
integer greater than or equal to the threshold and less than or equal
- to 28. The time interval this window represents depends on the inter-
- val between primary data points. If the FAILURES R\bRR\bRA\bA is implicitly cre-
- ated, the default value is 9.
+ to 28. The time interval this window represents depends on the
+ interval between primary data points. If the FAILURES R\bRR\bRA\bA is implicitly
+ created, the default value is 9.
T\bTh\bhe\be H\bHE\bEA\bAR\bRT\bTB\bBE\bEA\bAT\bT a\ban\bnd\bd t\bth\bhe\be S\bST\bTE\bEP\bP
Here is an explanation by Don Baarda on the inner workings of RRDtool.
@@ -343,13 +339,14 @@ T\bTh\bhe\be H\bHE\bEA\bAR\bRT\bTB\bBE\bEA\bAT\bT a\ban\bnd\bd t\bth\bhe\be S\bST\bTE\bEP\bP
builds Primary Data Points (PDPs) on every "step" interval. The PDPs
are then accumulated into the RRAs.
- The "heartbeat" defines the maximum acceptable interval between sam-
- ples/updates. If the interval between samples is less than "heartbeat",
- then an average rate is calculated and applied for that interval. If
- the interval between samples is longer than "heartbeat", then that
- entire interval is considered "unknown". Note that there are other
- things that can make a sample interval "unknown", such as the rate
- exceeding limits, or a sample that was explicitly marked as unknown.
+ The "heartbeat" defines the maximum acceptable interval between
+ samples/updates. If the interval between samples is less than
+ "heartbeat", then an average rate is calculated and applied for that
+ interval. If the interval between samples is longer than "heartbeat",
+ then that entire interval is considered "unknown". Note that there are
+ other things that can make a sample interval "unknown", such as the
+ rate exceeding limits, or a sample that was explicitly marked as
+ unknown.
The known rates during a PDP's "step" interval are used to calculate an
average rate for that PDP. If the total "unknown" time accounts for
@@ -363,10 +360,10 @@ T\bTh\bhe\be H\bHE\bEA\bAR\bRT\bTB\bBE\bEA\bAT\bT a\ban\bnd\bd t\bth\bhe\be S\bST\bTE\bEP\bP
multiple samples per PDP, and if you don't get them mark the PDP
unknown. A long heartbeat can span multiple "steps", which means it is
acceptable to have multiple PDPs calculated from a single sample. An
- extreme example of this might be a "step" of 5 minutes and a "heart-
- beat" of one day, in which case a single sample every day will result
- in all the PDPs for that entire day period being set to the same aver-
- age rate. _\b-_\b- _\bD_\bo_\bn _\bB_\ba_\ba_\br_\bd_\ba _\b<_\bd_\bo_\bn_\b._\bb_\ba_\ba_\br_\bd_\ba_\b@_\bb_\ba_\be_\bs_\by_\bs_\bt_\be_\bm_\bs_\b._\bc_\bo_\bm_\b>
+ extreme example of this might be a "step" of 5 minutes and a
+ "heartbeat" of one day, in which case a single sample every day will
+ result in all the PDPs for that entire day period being set to the same
+ average rate. _\b-_\b- _\bD_\bo_\bn _\bB_\ba_\ba_\br_\bd_\ba _\b<_\bd_\bo_\bn_\b._\bb_\ba_\ba_\br_\bd_\ba_\b@_\bb_\ba_\be_\bs_\by_\bs_\bt_\be_\bm_\bs_\b._\bc_\bo_\bm_\b>
time|
axis|
Here are a few hints on how to measure:
Temperature
- Usually you have some type of meter you can read to get the temper-
- ature. The temperature is not really connected with a time. The
- only connection is that the temperature reading happened at a cer-
- tain time. You can use the G\bGA\bAU\bUG\bGE\bE data source type for this. RRDtool
- will then record your reading together with the time.
+ Usually you have some type of meter you can read to get the
+ temperature. The temperature is not really connected with a time.
+ The only connection is that the temperature reading happened at a
+ certain time. You can use the G\bGA\bAU\bUG\bGE\bE data source type for this.
+ RRDtool will then record your reading together with the time.
Mail Messages
- Assume you have a method to count the number of messages trans-
- ported by your mailserver in a certain amount of time, giving you
- data like '5 messages in the last 65 seconds'. If you look at the
- count of 5 like an A\bAB\bBS\bSO\bOL\bLU\bUT\bTE\bE data type you can simply update the RRD
- with the number 5 and the end time of your monitoring period. RRD-
- tool will then record the number of messages per second. If at some
- later stage you want to know the number of messages transported in
- a day, you can get the average messages per second from RRDtool for
- the day in question and multiply this number with the number of
- seconds in a day. Because all math is run with Doubles, the preci-
- sion should be acceptable.
+ Assume you have a method to count the number of messages
+ transported by your mailserver in a certain amount of time, giving
+ you data like '5 messages in the last 65 seconds'. If you look at
+ the count of 5 like an A\bAB\bBS\bSO\bOL\bLU\bUT\bTE\bE data type you can simply update the
+ RRD with the number 5 and the end time of your monitoring period.
+ RRDtool will then record the number of messages per second. If at
+ some later stage you want to know the number of messages
+ transported in a day, you can get the average messages per second
+ from RRDtool for the day in question and multiply this number with
+ the number of seconds in a day. Because all math is run with
+ Doubles, the precision should be acceptable.
It's always a Rate
- RRDtool stores rates in amount/second for COUNTER, DERIVE and ABSO-
- LUTE data. When you plot the data, you will get on the y axis
+ RRDtool stores rates in amount/second for COUNTER, DERIVE and
+ ABSOLUTE data. When you plot the data, you will get on the y axis
amount/second which you might be tempted to convert to an absolute
amount by multiplying by the delta-time between the points. RRDtool
plots continuous data, and as such is not appropriate for plotting
RRA:MAX:0.5:12:2400 \
RRA:AVERAGE:0.5:12:2400
- This sets up an R\bRR\bRD\bD called _\bt_\be_\bm_\bp_\be_\br_\ba_\bt_\bu_\br_\be_\b._\br_\br_\bd which accepts one tempera-
- ture value every 300 seconds. If no new data is supplied for more than
- 600 seconds, the temperature becomes _\b*_\bU_\bN_\bK_\bN_\bO_\bW_\bN_\b*. The minimum acceptable
- value is -273 and the maximum is 5'000.
+ This sets up an R\bRR\bRD\bD called _\bt_\be_\bm_\bp_\be_\br_\ba_\bt_\bu_\br_\be_\b._\br_\br_\bd which accepts one
+ temperature value every 300 seconds. If no new data is supplied for
+ more than 600 seconds, the temperature becomes _\b*_\bU_\bN_\bK_\bN_\bO_\bW_\bN_\b*. The minimum
+ acceptable value is -273 and the maximum is 5'000.
A few archive areas are also defined. The first stores the temperatures
supplied for 100 hours (1'200 * 300 seconds = 100 hours). The second
RRA stores the minimum temperature recorded over every hour (12 * 300
seconds = 1 hour), for 100 days (2'400 hours). The third and the fourth
- RRA's do the same for the maximum and average temperature, respec-
- tively.
+ RRA's do the same for the maximum and average temperature,
+ respectively.
E\bEX\bXA\bAM\bMP\bPL\bLE\bE 2\b2
rrdtool create monitor.rrd --step 300 \
argument of HWPREDICT is missing, so the other R\bRR\bRA\bAs\bs will implicitly be
created with default parameter values. In this example, the forecasting
algorithm baseline adapts quickly; in fact the most recent one hour of
- observations (each at 5 minute intervals) accounts for 75% of the base-
- line prediction. The linear trend forecast adapts much more slowly.
+ observations (each at 5 minute intervals) accounts for 75% of the
+ baseline prediction. The linear trend forecast adapts much more slowly.
Observations made during the last day (at 288 observations per day)
- account for only 65% of the predicted linear trend. Note: these compu-
- tations rely on an exponential smoothing formula described in the LISA
- 2000 paper.
+ account for only 65% of the predicted linear trend. Note: these
+ computations rely on an exponential smoothing formula described in the
+ LISA 2000 paper.
- The seasonal cycle is one day (288 data points at 300 second inter-
- vals), and the seasonal adaption parameter will be set to 0.1. The RRD
- file will store 5 days (1'440 data points) of forecasts and deviation
- predictions before wrap around. The file will store 1 day (a seasonal
- cycle) of 0-1 indicators in the FAILURES R\bRR\bRA\bA.
+ The seasonal cycle is one day (288 data points at 300 second
+ intervals), and the seasonal adaption parameter will be set to 0.1. The
+ RRD file will store 5 days (1'440 data points) of forecasts and
+ deviation predictions before wrap around. The file will store 1 day (a
+ seasonal cycle) of 0-1 indicators in the FAILURES R\bRR\bRA\bA.
The same RRD file and R\bRR\bRA\bAs\bs are created with the following command,
which explicitly creates all specialized function R\bRR\bRA\bAs\bs.
RRA:DEVSEASONAL:288:0.1:2 \
RRA:FAILURES:288:7:9:5
- Of course, explicit creation need not replicate implicit create, a num-
- ber of arguments could be changed.
+ Of course, explicit creation need not replicate implicit create, a
+ number of arguments could be changed.
E\bEX\bXA\bAM\bMP\bPL\bLE\bE 3\b3
rrdtool create proxy.rrd --step 300 \
In the R\bRR\bRD\bD, the first data source stores the requests per second rate
during the interval. The second data source stores the total duration
- of all requests processed during the interval divided by 300. The COM-
- PUTE data source divides each PDP of the AccumDuration by the corre-
- sponding PDP of TotalRequests and stores the average request duration.
- The remainder of the RPN expression handles the divide by zero case.
+ of all requests processed during the interval divided by 300. The
+ COMPUTE data source divides each PDP of the AccumDuration by the
+ corresponding PDP of TotalRequests and stores the average request
+ duration. The remainder of the RPN expression handles the divide by
+ zero case.
A\bAU\bUT\bTH\bHO\bOR\bR
Tobias Oetiker <tobi@oetiker.ch>
-1.3.7 2008-06-11 RRDCREATE(1)
+1.3.8 2008-06-11 RRDCREATE(1)