Hello Bob, Friday, July 25, 2008, 4:58:54 PM, you wrote:
BF> On Fri, 25 Jul 2008, Robert Milkowski wrote: >> Both on 2540 and 6540 if you do not disable it your performance will >> be very bad especially for synchronous IOs as ZIL will force your >> array to flush its cache every time. If you are not using ZFS on any >> other storage than 2540 on your servers then put "set >> zfs:zfs_nocacheflush=1" in /etc/system and do a reboot. If you >> haven't done so it should help you considerably. BF> This does not seem wise since then data (records of trades) may be BF> lost if the system crashes or loses power. It is much better to apply BF> the firmware tweaks so that the 2540 reports that the data is written BF> as soon as it is safely in its NVRAM rather than waiting for it to be BF> on disk. ZFS should then perform rather well with low latency. Both cases are basically the same. Please notice I'm not talking about disabling ZIL, I'm talking about disabling cache flushes in ZFS. ZFS will still wait for the array to confirm that it did receive data (nvram). If you loose power the behavior will be the same - no difference here. -- Best regards, Robert Milkowski mailto:[EMAIL PROTECTED] http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
