On Mon, Dec 8, 2008 at 3:09 PM, milosz <[EMAIL PROTECTED]> wrote: > hi all, > > currently having trouble with sustained write performance with my setup... > > ms server 2003/ms iscsi initiator 2.08 w/intel e1000g nic directly connected > to snv_101 w/ intel e1000g nic. > > basically, given enough time, the sustained write behavior is perfectly > periodic. if i copy a large file to the iscsi target, iostat reports 10 > seconds or so of -no- writes to disk, just small reads... then 2-3 seconds of > disk-maxed writes, during which time windows reports the write performance > dropping to zero (disk queues maxed). > > so iostat will report something like this for each of my zpool disks (with > iostat -xtc 1) > > 1s: %b 0 > 2s: %b 0 > 3s: %b 0 > 4s: %b 0 > 5s: %b 0 > 6s: %b 0 > 7s: %b 0 > 8s: %b 0 > 9s: %b 0 > 10s: %b 0 > 11s: %b 100 > 12s: %b 100 > 13s: %b 100 > 14s: %b 0 > 15s: %b 0 > > it looks like solaris hangs out caching the writes and not actually > committing them to disk... when the cache gets flushed, the iscsitgt (or > whatever) just stops accepting writes. > > this is happening across controllers and zpools. also, a test copy of a 10gb > file from one zpool to another (not iscsi) yielded similar iostat results: 10 > seconds of big reads from the source zpool, 2-3 seconds of big writes to the > target zpool (target zpool is 5x bigger than source zpool). > > anyone got any ideas? point me in the right direction? > > thanks, > > milosz > -- > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >
Are you running at compression? I see this behavior with heavy loads, and GZIP compression enabled. What does 'zfs get compression' say? -- Brent Jones [EMAIL PROTECTED] _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
