James Lever wrote: > > On 07/07/2009, at 8:20 PM, James Andrewartha wrote: > >> Have you tried putting the slog on this controller, either as an SSD or >> regular disk? It's supported by the mega_sas driver, x86 and amd64 only. > > What exactly are you suggesting here? Configure one disk on this array > as a dedicated ZIL? Would that improve performance any over using all > disks with an internal ZIL?
I was mainly thinking about using the battery-backup write cache to eliminate the NFS latency. There's not much difference between internal vs dedicated ZIL if the disks are the same and on the same controller - dedicated ZIL wins come from using SSDs and battery-backed cache. http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide#Separate_Log_Devices > Is there a way to disable the write barrier in ZFS in the way you can > with Linux filesystems (-o barrier=0)? Would this make any difference? http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Cache_Flushes might help if the RAID card is still flushing to disk when ZFS asks it to even though it's safe in the battery-backed cache. -- James Andrewartha | Sysadmin Data Analysis Australia Pty Ltd _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
