Darren, thanks for reply. Still not clear to me thought.
The only purpose of the slog is to serve the ZIL. There may be many "ZIL"s on a single slog. >From Milek's blog: logbias=latency - data written to slog first logbias=throughtput - data written directly to dataset. Here's my problem. I have raidz device with SATA drives. I use it to serve iSCSI that is used for NTFS devices (bootable). Windows is constantly writing something to the devices and all writes are "synchronous". The result is that cache flushes are so often that the NCQ (queue dept) hardly goes above 0.5 resulting in very poor read/write performance. Disabling the ZIL (globally unfortunately) yields huge performance benefits for me as now my ZFS server is acting as a buffer, and Windows is far more snappy. And now I see queue > 3 occasionally and write performance doesn't suck big time. I am fine with loosing 5-10 even 15 seconds of data in the event of the crash, as far as the data is consistent. The "never turn off the ZIL" sounds scary, but if the only consequences are 15 (even 45) seconds of data loss .. i am willing to take this for my home environment. Opinions? -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
