Re: [zfs-discuss] what have you been buying for slog and l2arc?
On Fri, 3 Aug 2012, Neil Perrin wrote: For the slog, you should look for a SLC technology SSD which saves unwritten data on power failure. In Intel-speak, this is called "Enhanced Power Loss Data Protection". I am not running across any Intel SSDs which claim to match these requirements. - That shouldn't be necessary. ZFS flushes the write cache for any device written before returning from the synchronous request to ensure data stability. Yes, but the problem is that the write IOPS go way way down (and device lifetime suffers) if the device is not able to perform write caching. A consumer-grade device advertizing 70K write IOPS is definitely not going to offer anything like that if it actually flushes its cache when requested. A device with a reserve of energy sufficient to write its cache to backing FLASH on power fail will be able to defer cache flush requests. Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer,http://www.GraphicsMagick.org/ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Missing disk space
On Sat, Aug 4, 2012 at 12:00 AM, Burt Hailey wrote: > We do hourly snapshots. Two days ago I deleted 100GB of > data and did not see a corresponding increase in snapshot sizes. I’m new to > zfs and am reading the zfs admin handbook but I wanted to post this to get > some suggestions on what to look at. Use $ zfs get usedbysnapshots , and you will see where the space went. Listing the snapshots and looking at the USED column does not give you this information because it only shows what would be freed if _only_ this snapshot were destroyed. By destroying all of them, a lot more might become available. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] what have you been buying for slog and l2arc?
hi may be check out stec ssd or checkout the service manual of sun zfs appliance service manual to see the read and write ssd in the system regards Sent from my iPad On Aug 3, 2012, at 22:05, "Hung-Sheng Tsao (LaoTsao) Ph.D" wrote: > Intel 311 Series Larsen Creek 20GB 2.5" SATA II SLC Enterprise Solid State > Disk SSDSA2VP020G201 > > Average Rating > (12 reviews) > Write a Review > > Sent from my iPad > > On Aug 3, 2012, at 21:39, Bob Friesenhahn > wrote: > >> On Fri, 3 Aug 2012, Karl Rossing wrote: >> >>> I'm looking at >>> http://www.intel.com/content/www/us/en/solid-state-drives/solid-state-drives-ssd.html >>> wondering what I should get. >>> >>> Are people getting intel 330's for l2arc and 520's for slog? >> >> For the slog, you should look for a SLC technology SSD which saves unwritten >> data on power failure. In Intel-speak, this is called "Enhanced Power Loss >> Data Protection". I am not running across any Intel SSDs which claim to >> match these requirements. >> >> Extreme write IOPS claims in consumer SSDs are normally based on large write >> caches which can lose even more data if there is a power failure. >> >> Bob >> -- >> Bob Friesenhahn >> bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ >> GraphicsMagick Maintainer,http://www.GraphicsMagick.org/ >> ___ >> zfs-discuss mailing list >> zfs-discuss@opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] what have you been buying for slog and l2arc?
On Fri, Aug 03, 2012 at 08:39:55PM -0500, Bob Friesenhahn wrote: > For the slog, you should look for a SLC technology SSD which saves > unwritten data on power failure. In Intel-speak, this is called > "Enhanced Power Loss Data Protection". I am not running across any > Intel SSDs which claim to match these requirements. The http://www.intel.com/content/www/us/en/solid-state-drives/solid-state-drives-710-series.html seems to qualify: "Enhanced power-loss data protection. Saves all cached data in the process of being written before the Intel SSD 710 Series shuts down, which helps minimize potential data loss in the event of an unexpected system power loss." > Extreme write IOPS claims in consumer SSDs are normally based on large > write caches which can lose even more data if there is a power failure. Intel 311 with a good UPS would seem to be a reasonable tradeoff. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
