I thought there were perfomance issues with using SLOGs in general on OI since 148?
On Tue, Apr 24, 2012 at 16:11, Richard Elling < [email protected]> wrote: > On Apr 24, 2012, at 12:35 PM, Roy Sigurd Karlsbakk wrote: > > > Hi all > > > > There was a discussion some time back about some (or most?) SSDs not > honoring cache flushes, that is, something is written to, say, the SLOG, > and ZFS sends a flush(), the SSD issues a NOP and falsely acknowledges the > flush. > > Some people accused SSD vendors of not honoring cache flush. IIRC, the > allegations were not proven. > > > > > Now, I've gotten an offer for an SSD that looks good for SLOG, OCZ > Deneva 2 C SLC 30GB 2.5" SSD. This does not have supercap, but so long as > it honors cache flush, then it won't make a huge difference, since if a > write() happens, the SSD cache is flushed to the SSD media, this probably > won't take more than a handful of milliseconds, and the difference between > that and backing up the cache, seems minimal. > > I've known people to use that SSD without issue. > > Here is an article that sheds a little bit of light on the various SSD > designs. Unfortunately, it does not address the issue that HDDs have > with their volatile caches and why cache flush commands are so important. > > http://www.storagesearch.com/ssd-power-going-down.html > > -- richard > > -- > ZFS Performance and Training > [email protected] > +1-760-896-4422 > > > > _______________________________________________ > OpenIndiana-discuss mailing list > [email protected] > http://openindiana.org/mailman/listinfo/openindiana-discuss > -- Seconds to the drop, but it seems like hours. http://www.eff.org/ <http://www.eff.org/>http://creativecommons.org/ _______________________________________________ OpenIndiana-discuss mailing list [email protected] http://openindiana.org/mailman/listinfo/openindiana-discuss
