Product | Command Type |
---|---|
ClearCase | command |
Platform |
---|
UNIX |
Windows |
UNIX:
Windows:
NOTE: This utility is not intended for general use. It is intended primarily to help ClearCase engineering and Rational Technical Support personnel diagnose problems with the MVFS. For information on improving ClearCase client performance, see the Administrator's Guide.
The mvfsstat command displays MVFS usage and operating statistics, including cumulative statistics on MVFS cache usage, 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.
The -c option reports on the usage of the host's MVFS caches. This report is cumulative, covering the entire period since the MVFS was reloaded. The following example covers a 23-day period:
----------------- Fri Jul 16 16:20:16 1999 ---------------------
dnlc: 2267082 2229727( 98.4%) hit 1301984 dot 846301 dir 62901 reg 18541 noent
37355( 1.6%) miss 25099 events
42761( 1.9%) add 27820 dir 7368 reg 7573 noent
attr: 2355186 2349946( 99.8%) hit 120 lvut
5240( 0.2%) miss (3902cto+0gen+970timo+74new,294ev;35lvut)
57302 updates 5546unexp+2206exp mod, 2295 vmod
The following sections describe the particular statistics that are useful in tuning MVFS performance on a ClearCase client host.
The dnlc
section reports on usage of a name-lookup cache that maps pathnames to ClearCase 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):
| Number of times the current working directory was looked up (always a cache hit) |
| Number of times a directory object entry was found in the cache. |
| Number of times a file object entry was found in the cache. |
| Number of times a cached |
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
).
The attr
section reports on usage of a cache of stat(2) returns (UNIX) or object status inquiry records (Windows). This cache generally has hit rates comparable to that for the directory name lookup cache.
Identities: No special identity is required unless you specify the -z option. For -z, you must have one of the following identities:
root (UNIX)
Local Windows system administrator (Windows)
Member of the Windows Administrators group (Windows)
Mastership: (Replicated VOBs only) No mastership restrictions.
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mvfscache, mvfslog, mvfsstorage, mvfstime, mvfsversion
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