mvfsstat
The mvfsstat command displays MVFS use and operating statistics, including cumulative statistics on MVFS cache use, RPC statistics, cleartext I/O counts, vnode operation counts, and VFS operation counts. This data is useful for evaluating file system performance and determining whether MVFS cache sizes require adjustment.
Synopsis
- Linux® and the UNIX system:
mvfsstat [ –icrvVhalzAdF ] [ –o outfile] [ time ] [ count ]
- Windows®:
mvfsstat [ –iIcrvVhalzAdF ] [ –o outfile] [ time ] [ count ]
MVFS cache statistics
The –c option reports on the use of the host’s MVFS caches. This report is cumulative, covering the entire period since the MVFS was started. The following sections describe the particular statistics that are useful in tuning MVFS performance on an HCL VersionVault client host.
Directory name lookup cache (dnlc). The dnlc section
reports on use of a name-lookup cache that maps pathnames to HCL
VersionVault identifiers.
Note that the value precedes the keyword. For example, 1301984 dot means
that the reported value of the dot statistic is 1301984.
Cache
hits. The hit line reports on the number of times an
entry type was found in the cache (hit):
dot- Number of times the current working directory was looked up (always a cache hit)
dir- Number of times a directory object entry was found in the cache
reg- Number of times a file object entry was found in the cache
noent- Number of times a cached
File not found(ENOENT) entry was found
This cache has low hit rates (around 50%) for activities that walk a large tree, for example, a find command, or a recursive clearmake that examines many files and determines that nothing needs to be built.
Cache misses. The miss line
reports on total cache misses. The events value is the number
of cache misses that occurred because of a significant VOB event, a time-out
of the entry, or vnode recycling. Cache misses can occur because there was
no entry in the cache. The total number of cache misses equals the events value
plus the number of misses occurring because there was no entry in the cache.
Cache
additions. The add line reports on cache misses that
occurred because a new entry was being added to the cache. The additions are
categorized as directory entries (dir), file entries (reg),
and ENOENT entries (noent).
Attribute cache. The attr section reports on use of a cache of
stat returns (Linux and the UNIX system) or object status inquiry records (Windows). This cache generally
has hit rates comparable to those for the directory name lookup cache.
Options and arguments
- time
- Time in seconds between samples. Display deltas on each sample. If you omit this option, only the absolute values of all information are printed.
- count
- Number of samples. If omitted, defaults to "infinite".
- –o outfile
- Writes the output to outfile.
- –i
- Displays cleartext I/O counts and wait times.
- –I
- Displays count and wait times for Windows I/O Request Packets that the MVFS has processed.
- –c
- Displays statistics for the MVFS caches (see MVFS cache statistics).
- –r
- Displays MVFS remote procedure call (RPC) statistics. These statistics
include both counts and real-time waited. Real-time waited may be greater
than 100% of a sample period in two cases:
- When an operation takes longer to complete than the sample period; for example, 60 seconds of wait time is recorded in a 30-second sample.
- Multiple processes are waiting at the same time.
In general, real-time percentages are meaningful only when a single process is accessing a VOB.
- –v
- Displays counts of vnode operations.
- –V
- Displays counts of vfs operations.
- –h
- Displays an RPC histogram. Cleartext fetch RPCs are tallied separately from all other RPCs.
- –a
- Displays auditing statistics.
- –l
- Adds more detail to the statistics generated by –c, –r, –i, –I, –v, or –V, by providing a breakdown by individual operations. With –c, also provides per-cache-entry hit ratios.
- –z
- (Requires privileged user status.) Resets all running counters to zero.
- –A
- Displays all statistics.
- –d
- With –c or –A, displays additional debugging information for use in diagnosing problems. Use this option only under direction from HCL Customer Support.
- –F
- Displays statistics for mnode operations and the directory name lookup cache. Use this option only under direction from HCL Customer Support.