> Maybe I didn't make my intention clear. UFS with directio is > reasonably close to a raw disk from my application's perspective: when > the app writes to a file location, no buffering happens. My goal is to > find a way to duplicate this on ZFS.
There really is no need to do this on ZFS. Using an SLOG device (ZIL on an SSD) will allow ZFS to do its caching transpararently to the application. Successive read operations will read from the cache if that's available and writes will go to the SLOG _and_ the ARC for successive commits. So long the SLOG device supports cache flush, or have a supercap/BBU, your data will be safe. > Setting primarycache didn't eliminate the buffering, using O_DSYNC > (whose side effects include elimination of buffering) made it > ridiculously slow: none of the things I tried eliminated buffering, > and just buffering, on ZFS. > > From the discussion so far my feeling is that ZFS is too different > from UFS that there's simply no way to achieve this goal... See above - ZFS is quite safe to use for this, given a good hardware configuration. Vennlige hilsener / Best regards roy -- Roy Sigurd Karlsbakk (+47) 97542685 r...@karlsbakk.net http://blogg.karlsbakk.net/ -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av idiomer med fremmed opprinnelse. I de fleste tilfeller eksisterer adekvate og relevante synonymer på norsk. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
