1 /*****************************************************************************
2 * RRDtool 1.2.99907080300 Copyright by Tobi Oetiker, 1997-2007
3 *****************************************************************************
4 * rrd_format.h RRD Database Format header
5 *****************************************************************************/
12 /*****************************************************************************
13 * put this in your /usr/lib/magic file (/etc/magic on HPUX)
15 * # rrd database format
16 * 0 string RRD\0 rrd file
17 * >5 string >\0 version '%s'
19 *****************************************************************************/
21 #define RRD_COOKIE "RRD"
22 /* #define RRD_VERSION "0002" */
23 /* changed because microsecond precision requires another field */
24 #define RRD_VERSION "0004"
25 #define RRD_VERSION3 "0003"
26 #define FLOAT_COOKIE 8.642135E130
28 #include "rrd_nan_inf.h"
30 typedef union unival {
36 /****************************************************************************
37 * The RRD Database Structure
38 * ---------------------------
40 * In oder to properly describe the database structure lets define a few
43 * ds - Data Source (ds) providing input to the database. A Data Source (ds)
44 * can be a traffic counter, a temperature, the number of users logged
45 * into a system. The rrd database format can handle the input of
46 * several Data Sources (ds) in a singe database.
48 * dst - Data Source Type (dst). The Data Source Type (dst) defines the rules
49 * applied to Build Primary Data Points from the input provided by the
52 * pdp - Primary Data Point (pdp). After the database has accepted the
53 * input from the data sources (ds). It starts building Primary
54 * Data Points (pdp) from the data. Primary Data Points (pdp)
55 * are evenly spaced along the time axis (pdp_step). The values
56 * of the Primary Data Points are calculated from the values of
57 * the data source (ds) and the exact time these values were
58 * provided by the data source (ds).
60 * pdp_st - PDP Start (pdp_st). The moments (pdp_st) in time where
61 * these steps occur are defined by the moments where the
62 * number of seconds since 1970-jan-1 modulo pdp_step equals
65 * cf - Consolidation Function (cf). An arbitrary Consolidation Function (cf)
66 * (averaging, min, max) is applied to the primary data points (pdp) to
67 * calculate the consolidated data point.
69 * cdp - Consolidated Data Point (cdp) is the long term storage format for data
70 * in the rrd database. Consolidated Data Points represent one or
71 * several primary data points collected along the time axis. The
72 * Consolidated Data Points (cdp) are stored in Round Robin Archives
75 * rra - Round Robin Archive (rra). This is the place where the
76 * consolidated data points (cdp) get stored. The data is
77 * organized in rows (row) and columns (col). The Round Robin
78 * Archive got its name from the method data is stored in
79 * there. An RRD database can contain several Round Robin
80 * Archives. Each Round Robin Archive can have a different row
81 * spacing along the time axis (pdp_cnt) and a different
82 * consolidation function (cf) used to build its consolidated
85 * rra_st - RRA Start (rra_st). The moments (rra_st) in time where
86 * Consolidated Data Points (cdp) are added to an rra are
87 * defined by the moments where the number of seconds since
88 * 1970-jan-1 modulo pdp_cnt*pdp_step equals zero (rra_st).
90 * row - Row (row). A row represent all consolidated data points (cdp)
91 * in a round robin archive who are of the same age.
93 * col - Column (col). A column (col) represent all consolidated
94 * data points (cdp) in a round robin archive (rra) who
95 * originated from the same data source (ds).
99 /****************************************************************************
100 * POS 1: stat_head_t static header of the database
101 ****************************************************************************/
103 typedef struct stat_head_t {
105 /* Data Base Identification Section ** */
106 char cookie[4]; /* RRD */
107 char version[5]; /* version of the format */
108 double float_cookie; /* is it the correct double
109 * representation ? */
111 /* Data Base Structure Definition **** */
112 unsigned long ds_cnt; /* how many different ds provide
113 * input to the rrd */
114 unsigned long rra_cnt; /* how many rras will be maintained
116 unsigned long pdp_step; /* pdp interval in seconds */
118 unival par[10]; /* global parameters ... unused
123 /****************************************************************************
124 * POS 2: ds_def_t (* ds_cnt) Data Source definitions
125 ****************************************************************************/
127 enum dst_en { DST_COUNTER = 0, /* data source types available */
134 enum ds_param_en { DS_mrhb_cnt = 0, /* minimum required heartbeat. A
135 * data source must provide input at
136 * least every ds_mrhb seconds,
137 * otherwise it is regarded dead and
138 * will be set to UNKNOWN */
139 DS_min_val, /* the processed input of a ds must */
140 DS_max_val, /* be between max_val and min_val
141 * both can be set to UNKNOWN if you
142 * do not care. Data outside the limits
144 DS_cdef = DS_mrhb_cnt
145 }; /* pointer to encoded rpn
146 * expression only applies to DST_CDEF */
148 /* The magic number here is one less than DS_NAM_SIZE */
149 #define DS_NAM_FMT "%19[a-zA-Z0-9_-]"
150 #define DS_NAM_SIZE 20
152 #define DST_FMT "%19[A-Z]"
155 typedef struct ds_def_t {
156 char ds_nam[DS_NAM_SIZE]; /* Name of the data source (null terminated) */
157 char dst[DST_SIZE]; /* Type of data source (null terminated) */
158 unival par[10]; /* index of this array see ds_param_en */
161 /****************************************************************************
162 * POS 3: rra_def_t ( * rra_cnt) one for each store to be maintained
163 ****************************************************************************/
164 enum cf_en { CF_AVERAGE = 0, /* data consolidation functions */
169 /* An array of predictions using the seasonal
170 * Holt-Winters algorithm. Requires an RRA of type
171 * CF_SEASONAL for this data source. */
173 /* An array of seasonal effects. Requires an RRA of
174 * type CF_HWPREDICT for this data source. */
176 /* An array of deviation predictions based upon
177 * smoothed seasonal deviations. Requires an RRA of
178 * type CF_DEVSEASONAL for this data source. */
180 /* An array of smoothed seasonal deviations. Requires
181 * an RRA of type CF_HWPREDICT for this data source.
184 /* HWPREDICT that follows a moving baseline */
186 /* new entries must come last !!! */
189 /* A binary array of failure indicators: 1 indicates
190 * that the number of violations in the prescribed
191 * window exceeded the prescribed threshold. */
193 #define MAX_RRA_PAR_EN 10
194 enum rra_par_en { RRA_cdp_xff_val = 0, /* what part of the consolidated
195 * datapoint must be known, to produce a
196 * valid entry in the rra */
198 /* exponential smoothing parameter for the intercept in
199 * the Holt-Winters prediction algorithm. */
201 /* exponential smoothing parameter for the slope in
202 * the Holt-Winters prediction algorithm. */
203 RRA_dependent_rra_idx,
204 /* For CF_HWPREDICT: index of the RRA with the seasonal
205 * effects of the Holt-Winters algorithm (of type
207 * For CF_DEVPREDICT: index of the RRA with the seasonal
208 * deviation predictions (of type CF_DEVSEASONAL).
209 * For CF_SEASONAL: index of the RRA with the Holt-Winters
210 * intercept and slope coefficient (of type CF_HWPREDICT).
211 * For CF_DEVSEASONAL: index of the RRA with the
212 * Holt-Winters prediction (of type CF_HWPREDICT).
213 * For CF_FAILURES: index of the CF_DEVSEASONAL array.
215 RRA_seasonal_smooth_idx,
216 /* For CF_SEASONAL and CF_DEVSEASONAL:
217 * an integer between 0 and row_count - 1 which
218 * is index in the seasonal cycle for applying
219 * the period smoother. */
220 RRA_failure_threshold,
221 /* For CF_FAILURES, number of violations within the last
222 * window required to mark a failure. */
223 RRA_seasonal_gamma = RRA_hw_alpha,
224 /* exponential smoothing parameter for seasonal effects.
226 RRA_delta_pos = RRA_hw_alpha,
227 RRA_delta_neg = RRA_hw_beta,
228 /* confidence bound scaling parameters for the
229 * the FAILURES RRA. */
230 RRA_window_len = RRA_seasonal_smooth_idx
233 /* For CF_FAILURES, the length of the window for measuring
236 #define CF_NAM_FMT "%19[A-Z]"
237 #define CF_NAM_SIZE 20
239 typedef struct rra_def_t {
240 char cf_nam[CF_NAM_SIZE]; /* consolidation function (null term) */
241 unsigned long row_cnt; /* number of entries in the store */
242 unsigned long pdp_cnt; /* how many primary data points are
243 * required for a consolidated data
245 unival par[MAX_RRA_PAR_EN]; /* index see rra_param_en */
250 /****************************************************************************
251 ****************************************************************************
252 ****************************************************************************
253 * LIVE PART OF THE HEADER. THIS WILL BE WRITTEN ON EVERY UPDATE *
254 ****************************************************************************
255 ****************************************************************************
256 ****************************************************************************/
257 /****************************************************************************
259 ****************************************************************************/
261 typedef struct live_head_t {
262 time_t last_up; /* when was rrd last updated */
263 long last_up_usec; /* micro seconds part of the
264 update timestamp. Always >= 0 */
268 /****************************************************************************
269 * POS 5: pdp_prep_t (* ds_cnt) here we prepare the pdps
270 ****************************************************************************/
271 #define LAST_DS_LEN 30 /* DO NOT CHANGE THIS ... */
273 enum pdp_par_en { PDP_unkn_sec_cnt = 0, /* how many seconds of the current
274 * pdp value is unknown data? */
277 }; /* current value of the pdp.
278 this depends on dst */
280 typedef struct pdp_prep_t {
281 char last_ds[LAST_DS_LEN]; /* the last reading from the data
282 * source. this is stored in ASCII
283 * to cater for very large counters
284 * we might encounter in connection
286 unival scratch[10]; /* contents according to pdp_par_en */
289 /* data is passed from pdp to cdp when seconds since epoch modulo pdp_step == 0
290 obviously the updates do not occur at these times only. Especially does the
291 format allow for updates to occur at different times for each data source.
292 The rules which makes this work is as follows:
294 * DS updates may only occur at ever increasing points in time
295 * When any DS update arrives after a cdp update time, the *previous*
296 update cycle gets executed. All pdps are transfered to cdps and the
297 cdps feed the rras where necessary. Only then the new DS value
298 is loaded into the PDP. */
301 /****************************************************************************
302 * POS 6: cdp_prep_t (* rra_cnt * ds_cnt ) data prep area for cdp values
303 ****************************************************************************/
304 #define MAX_CDP_PAR_EN 10
305 #define MAX_CDP_FAILURES_IDX 8
306 /* max CDP scratch entries avail to record violations for a FAILURES RRA */
307 #define MAX_FAILURES_WINDOW_LEN 28
308 enum cdp_par_en { CDP_val = 0,
309 /* the base_interval is always an
312 /* how many unknown pdp were
313 * integrated. This and the cdp_xff
314 * will decide if this is going to
315 * be a UNKNOWN or a valid value */
317 /* Current intercept coefficient for the Holt-Winters
318 * prediction algorithm. */
319 CDP_hw_last_intercept,
320 /* Last iteration intercept coefficient for the Holt-Winters
321 * prediction algorihtm. */
323 /* Current slope coefficient for the Holt-Winters
324 * prediction algorithm. */
326 /* Last iteration slope coeffient. */
328 /* Number of sequential Unknown (DNAN) values + 1 preceding
329 * the current prediction.
332 /* Last iteration count of Unknown (DNAN) values. */
334 /* optimization for bulk updates: the value of the first CDP
335 * value to be written in the bulk update. */
336 CDP_secondary_val = 9,
337 /* optimization for bulk updates: the value of subsequent
338 * CDP values to be written in the bulk update. */
339 CDP_hw_seasonal = CDP_hw_intercept,
340 /* Current seasonal coefficient for the Holt-Winters
341 * prediction algorithm. This is stored in CDP prep to avoid
342 * redundant seek operations. */
343 CDP_hw_last_seasonal = CDP_hw_last_intercept,
344 /* Last iteration seasonal coeffient. */
345 CDP_seasonal_deviation = CDP_hw_intercept,
346 CDP_last_seasonal_deviation = CDP_hw_last_intercept,
347 CDP_init_seasonal = CDP_null_count
350 /* init_seasonal is a flag which when > 0, forces smoothing updates
351 * to occur when rra_ptr.cur_row == 0 */
353 typedef struct cdp_prep_t {
354 unival scratch[MAX_CDP_PAR_EN];
355 /* contents according to cdp_par_en *
356 * init state should be NAN */
360 /****************************************************************************
361 * POS 7: rra_ptr_t (* rra_cnt) pointers to the current row in each rra
362 ****************************************************************************/
364 typedef struct rra_ptr_t {
365 unsigned long cur_row; /* current row in the rra */
369 /****************************************************************************
370 ****************************************************************************
371 * One single struct to hold all the others. For convenience.
372 ****************************************************************************
373 ****************************************************************************/
374 typedef struct rrd_t {
375 stat_head_t *stat_head; /* the static header */
376 ds_def_t *ds_def; /* list of data source definitions */
377 rra_def_t *rra_def; /* list of round robin archive def */
378 live_head_t *live_head;
379 pdp_prep_t *pdp_prep; /* pdp data prep area */
380 cdp_prep_t *cdp_prep; /* cdp prep area */
381 rra_ptr_t *rra_ptr; /* list of rra pointers */
382 rrd_value_t *rrd_value; /* list of rrd values */
385 /****************************************************************************
386 ****************************************************************************
387 * AFTER the header section we have the DATA STORAGE AREA it is made up from
388 * Consolidated Data Points organized in Round Robin Archives.
389 ****************************************************************************
390 ****************************************************************************
393 (0,0) .................... ( ds_cnt -1 , 0)
397 (0, row_cnt -1) ... (ds_cnt -1, row_cnt -1)
404 ****************************************************************************/