Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
t == taemun tae...@gmail.com writes: t I would note that the Seagate 2TB LP has a 0.32% Annualised t Failure Rate. bullshit. pgpsMvTxl5Ghd.pgp Description: PGP signature ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
On 2 December 2010 16:17, Miles Nordin car...@ivy.net wrote: t == taemun tae...@gmail.com writes: t I would note that the Seagate 2TB LP has a 0.32% Annualised t Failure Rate. bullshit. Apologies, should have read: Specified Annualised Failure Rate. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
Not sure where you got this figure from, the Barracuda Green (http://www.seagate.com/docs/pdf/datasheet/disc/ds1720_barracuda_green.pdf) is a different drive to the one we've been talking about in this thread (http://www.seagate.com/docs/pdf/datasheet/disc/ds_barracuda_lp.pdf). I would note that the Seagate 2TB LP has a 0.32% Annualised Failure Rate. ie, in a given sample (which aren't overheating, etc) 32 from every 10,000 should fail. I *believe* that the Power On-Hours on the Barra Green is simply saying that it is designed for 24/7 usage. It's a per year number. I couldn't imagine them specifying the number of hours before failure like that, just below an AFR of 0.43. Whoops, yes, that's what I did, I assumed that LP == Green, but I guess that is not the case. I got 2 from the newegg sale, I'll post my impressions once I get them and added to a pool...assuming they survived newegg's rather subpar hard drive packaging process. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] Seagate ST32000542AS and ZFS perf
Hi, Does anyone use Seagate ST32000542AS disks with ZFS? I wonder if the performance is not that ugly as with WD Green WD20EARS disks. Thanks, -- Piotr Jasiukajtis | estibi | SCA OS0072 http://estseg.blogspot.com ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
On 29 November 2010 20:39, GMAIL piotr.jasiukaj...@gmail.com wrote: Does anyone use Seagate ST32000542AS disks with ZFS? I wonder if the performance is not that ugly as with WD Green WD20EARS disks. I'm using these drives for one of the vdevs in my pool. The pool was created with ashift=12 (zpool binary from http://digitaldj.net/2010/11/03/zfs-zpool-v28-openindiana-b147-4k-drives-and-you/), which limits the minimum block size to 4KB, the same as the physical block size on these drives. I haven't noticed any performance issues. These obviously aren't 7200rpm drives, so you can't expect them to match those in random IOPS. I'm also using a set of Samsung HD204UI's in the pool. I would urge you to consider a 2^n + p number of disks. For raidz, p = 1, so an acceptable number of total drives is 3, 5 or 9. raidz2 has two parity drives, hence 4, 6 or 10. These vdev widths ensure that the data blocks are divided into nicer sizes. A 128KB block in a 9-wide raidz vdev will be split into 128/(9-1) = 16KB chunks. Cheers, ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
Thanks, I need to try modified zpool than. On Nov 29, 2010, at 10:50 AM, taemun wrote: On 29 November 2010 20:39, GMAIL piotr.jasiukaj...@gmail.com wrote: Does anyone use Seagate ST32000542AS disks with ZFS? I wonder if the performance is not that ugly as with WD Green WD20EARS disks. I'm using these drives for one of the vdevs in my pool. The pool was created with ashift=12 (zpool binary from http://digitaldj.net/2010/11/03/zfs-zpool-v28-openindiana-b147-4k-drives-and-you/), which limits the minimum block size to 4KB, the same as the physical block size on these drives. I haven't noticed any performance issues. These obviously aren't 7200rpm drives, so you can't expect them to match those in random IOPS. I'm also using a set of Samsung HD204UI's in the pool. I would urge you to consider a 2^n + p number of disks. For raidz, p = 1, so an acceptable number of total drives is 3, 5 or 9. raidz2 has two parity drives, hence 4, 6 or 10. These vdev widths ensure that the data blocks are divided into nicer sizes. A 128KB block in a 9-wide raidz vdev will be split into 128/(9-1) = 16KB chunks. Cheers, ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss -- Piotr Jasiukajtis | estibi | SCA OS0072 http://estseg.blogspot.com ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
On Mon, November 29, 2010 04:50, taemun wrote: I would urge you to consider a 2^n + p number of disks. For raidz, p = 1, so an acceptable number of total drives is 3, 5 or 9. raidz2 has two parity drives, hence 4, 6 or 10. These vdev widths ensure that the data blocks are divided into nicer sizes. A 128KB block in a 9-wide raidz vdev will be split into 128/(9-1) = 16KB chunks. Wouldn't nine disks in a a one-parity RAID set be pushing reliability a bit? Notwithstanding things like rebuild/resilver time and IOps, anyone know of a maximum recommended size to minimize the chances of losing an entire pool? ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
I'm using these drives for one of the vdevs in my pool. The pool was created with ashift=12 (zpool binary from http://digitaldj.net/2010/11/03/zfs-zpool-v28-openindiana-b147-4k-drives-and-you/), which limits the minimum block size to 4KB, the same as the physical block size on these drives. I haven't noticed any performance issues. These obviously aren't 7200rpm drives, so you can't expect them to match those in random IOPS. The Seagate datasheet for those parts report 512-byte sectors. What is the deal with the ST32000542AS: native 512-byte sectors, native 4k-byte sector with selectable emulation, or native 4k-byte sectors with 512-byte sector emulation always on? Also, just a side note, I believe these drives achieve their low-power status with the reduced RPM (5900rpm), not with the head parking style power-management that WD Green drives use? The latter I've read is rather unsuitable for RAID operation (especially with HW RAID controllers). ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
On Mon, Nov 29, 2010 at 10:59 AM, Krunal Desai mov...@gmail.com wrote: The Seagate datasheet for those parts report 512-byte sectors. What is the deal with the ST32000542AS: native 512-byte sectors, native 4k-byte sector with selectable emulation, or native 4k-byte sectors with 512-byte sector emulation always on? Disregard; if I understand correctly, Seagate has proprietary SmartAlign tech that takes care of 4K sectors (see links below). I can't seem to find any real whitepaper style explanation of the method though, but I assume it either: 1. does a really good job of 512-byte emulation that results in little to no performance degradation (http://consumer.media.seagate.com/2010/06/the-digital-den/advanced-format-drives-with-smartalign/ references test data) 2. dynamically looks to see if it even needs to do anything; if the host OS is sending it requests that all 4k-aware/aligned, all is well. Newegg has these on sale today for $69.99; sadly the limit is 2. I think I'll pick two up and use them for some tests and stock up on this model drive. Though, the power-on hours count seems rather low for me...8760 hours, or just 1 year of 24/7 operation. I may have to revisit power management in OpenSolaris (or upgrade to OpenIndiana) to see if my disks are spinning down when they are supposed too. Links: http://www.seagate.com/ww/v/index.jsp?locale=en-USname=advanced-format-migration-to-4k-tpcvgnextoid=746f43fce2489210VgnVCM101a48090aRCRD http://www.seagate.com/docs/pdf/whitepaper/tp615_smartalign_for_af_4k.pdf ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Seagate ST32000542AS and ZFS perf
On 30 November 2010 03:09, Krunal Desai mov...@gmail.com wrote: I assume it either: 1. does a really good job of 512-byte emulation that results in little to no performance degradation ( http://consumer.media.seagate.com/2010/06/the-digital-den/advanced-format-drives-with-smartalign/ references test data) 2. dynamically looks to see if it even needs to do anything; if the host OS is sending it requests that all 4k-aware/aligned, all is well. My understanding is that this is merely saying that it will *align* the data correctly, with Windows XP, regardless of where Windows XP asks for the first sector to be. This has nothing to do with 512B random writes. Though, the power-on hours count seems rather low for me...8760 hours, or just 1 year of 24/7 operation. Not sure where you got this figure from, the Barracuda Green ( http://www.seagate.com/docs/pdf/datasheet/disc/ds1720_barracuda_green.pdf) is a different drive to the one we've been talking about in this thread ( http://www.seagate.com/docs/pdf/datasheet/disc/ds_barracuda_lp.pdf). I would note that the Seagate 2TB LP has a 0.32% Annualised Failure Rate. ie, in a given sample (which aren't overheating, etc) 32 from every 10,000 should fail. I *believe* that the Power On-Hours on the Barra Green is simply saying that it is designed for 24/7 usage. It's a per year number. I couldn't imagine them specifying the number of hours before failure like that, just below an AFR of 0.43. Cheers, ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
