●
Default setting:
retry
or
1
●
Associated environment variable: none
●
Additional notes: none
ro_cache
/
no_ro_cache
ro_cache
enables read-only caching for files on writable mount points. Files
opened with read-only permissions in
ro_cache
mode are treated as if they
are on a DVS read-only cached mount point. If the file has any concurrent
open that has write permissions, all instances of that file revert to the default
no_ro_cache
mode for the current and subsequent reads.
no_ro_cache
disables read-only caching for files on writable mount points.
●
Default setting:
no_ro_cache
or
0
●
Associated environment variable: none
●
Additional notes: none
userenv
/
nouserenv
userenv
argument specifies that DVS must honor end user environment
variable overrides for DVS mount options.
nouserenv
argument allows the administrator to block end user environment
variable overrides for DVS mount options.
●
Default setting:
userenv
or
1
●
Associated environment variable: none
●
Additional notes: none
6.1.4
DVS Environment Variables
By default, user environment variables allow client override of options specified in the
/etc/fstab
entry and are
evaluated a file is opened by DVS. However, if the
nouserenv
option is specified in the DVS entry, then user
environment variables are disabled.
The following environment variables are for use in the default case:
Variable Name
Options Purpose
DVS_ATOMIC
on|off
Overrides the
atomic
or
noatomic
mount options.
DVS_BLOCKSIZE
n
A nonzero number,
n
overrides the
blksize
mount option.
DVS_CACHE
on|off
Overrides the
cache
or
nocache
mount options. This option is available only
for read-only mount points and is ignored for writeable mount points.
DVS_CACHE_READ_SZ
n
A positive integer,
n
overrides the
cache_read_sz
mount option.
DVS_CLOSESYNC
on|off
Overrides the
closesync
or
noclosesync
mount options.
DVS_DATASYNC
on|off
Overrides the
datasync
or
nodatasync
mount options.
NOTE: Setting
DVS_DATASYNC
to
on
can slow down an application
considerably. Consider using periodic sync.
Cray DVS
S3016
149
