Viewing the SmartIO cache statistics


Viewing the SmartIO cache statistics
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Use the sfcache stat command to display the cache statistics for the system.

Table: Cache statistics describes the cache statistics in the output.

Table: Cache statistics

Field	Description
HIT RATIO (VxVM cache)	Percentage of total I/Os that are satisfied from the cache. Displayed for reads and writes.
ART(Hit)ms (VxVM cache)	Average response time for I/Os that are satisfied from the cache.Displayed for reads (RD) and writes (WR).
ART(Miss)ms (VxVM cache)	Average response time for I/Os that are not satisfied from the cache. Displayed for r reads (RD) and writes (WR) .
BYTES (VxVM cache)	Total size of I/Os for reads (RD) and writes (WR).
NAME (VxVM cache)	Name of the cache area.
TYPE (VxVM cache)	Whether the cache area is VxVM or VxFS.
%CACHE (VxVM cache)	Percentage of the cache area that is currently used for data.for all data objects.
Cache Size (VxFS cache)	Size of the cache area.
Cache Utilization (VxFS cache)	Percentage of the cache area that is currently used for data.
File Systems Using Cache (VxFS cache)	Number of file systems using the cache.
Writeback Cache Use Limit (VxFS cache)	Size of the cache area that is used for writeback. You can set the size with the writeback_size attribute. If no size is set, the field displays Unlimited. See Tuning the writeback caching.
Writeback Flush Timelag	Interval between when the data is written to the cache and when it is flushed to the disk. If the Writeback Flush Timelag is small, such as 10 seconds, then sfcache statistics will not show. Data is flushed to disk faster. In this case, you can determine the caching usage based on the WB Hit Ratio.
Hit Ratio (VxFS cache)	Percentage of total I/Os that are satisfied from the cache. Displayed for reads and writes.
Data Read (VxFS cache)	Data read from the cache.
Data Written (VxFS cache)	Data written to the cache.
Files Cached (VxFS cache)	Number of files present in the cache.
Files Pinned (VxFS cache)	Number of pinned files in the cache.
Data Pinned (VxFS cache)	Amount of data pinned in the cache.

To view the cache statistics

Use the following command:

# sfcache stat

                       HIT RATIO    ART(Hit)ms   ART(Miss)ms    BYTES
NAME            %CACHE RD    WR     RD   WR      RD    WR     RD     WR
TYPE: VxVM
sfcachearea_1   13.43  91.24 94.20  0.142 0.819  0.414 0.798  15.31g 4.21g

TYPE: VxFS
NAME: sfcachearea_2
               Cache Size:    48.0 GB
        Cache Utilization:    72.2 MB ( 0.15 %)
 File Systems Using Cache:       1
Writeback Cache Use Limit:  Unlimited
  Writeback Flush Timelag:      10 s

Read Cache
Hit Ratio  Data Read  Data Written  Files Cached  Files Pinned  Data Pinned
   0.00 %       0 KB          0 KB             0             0         0 KB

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Tuning the writeback caching	Home	Viewing the detailed caching stats for a VxVM cache area