Hi all, I have been asked to build a new server and would like to get some opinions on how to setup a zfs pool for the application running on the server. The server will be exclusively for running netbackup application. Now which would be better? setting up a raidz pool with 6x146gig drives or setting up 3 mirrors of 2x146gig into a pool? Currently I have it setup with the mirrors.. but am wondering if the raidz possibility would be a better choice. Thanks in advance. -- This message posted from opensolaris.org
On 29 October, 2008 - Mike sent me these 0,7K bytes:> Hi all, > > I have been asked to build a new server and would like to get some > opinions on how to setup a zfs pool for the application running on the > server. The server will be exclusively for running netbackup > application. > > Now which would be better? setting up a raidz pool with 6x146gig > drives or setting up 3 mirrors of 2x146gig into a pool? > > Currently I have it setup with the mirrors.. but am wondering if the > raidz possibility would be a better choice.Define "better"? The raidz option will give you more storage at less performance.. The mirror thing has the possibility of achieving higher reliability.. 1 to 3 disks can fail without interruptions, depending on how Murphy picks them.. The raidz1 one can handle 1 disk only.. /Tomas -- Tomas ?gren, stric at acc.umu.se, http://www.acc.umu.se/~stric/ |- Student at Computing Science, University of Ume? `- Sysadmin at {cs,acc}.umu.se
By Better I meant the best practice for a server running the Netbackup application. I am not seeing how using raidz would be a performance hit. Usually stripes perform faster than mirrors. -- This message posted from opensolaris.org
On Wed, 29 Oct 2008, Tomas ?gren wrote:> > The raidz option will give you more storage at less performance.. The > mirror thing has the possibility of achieving higher reliability.. 1 to > 3 disks can fail without interruptions, depending on how Murphy picks > them.. The raidz1 one can handle 1 disk only..Mirrors also offer ease of administration. Half the drives can be administratively removed and the pool will still work. The sizes of drives in individual pairs can be updated one by one in order to offer more space rather than requiring all of the drives in a raidz to be replaced before the space is seen. Resilvering will be faster when using mirrors since only one disk has to be read to reconstruct the data. If you feel uneasy about reliability, then you can easily use tripple mirroring. However raidz2 offers more reliability than dual-mirrors and raidz1. Bob =====================================Bob Friesenhahn bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
On Wed, 29 Oct 2008, Mike wrote:> I am not seeing how using raidz would be a performance hit. Usually > stripes perform faster than mirrors.The mirrors load-share and offer a lot more disk seeking capacity (more IOPS). Bob =====================================Bob Friesenhahn bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
On Wed, Oct 29, 2008 at 3:42 PM, Mike <mrmike77 at gmail.com> wrote:> By Better I meant the best practice for a server running the Netbackup application. > > I am not seeing how using raidz would be a performance hit. Usually stripes perform faster than mirrors.raidz performs reads from all devices in parallel, so you get 1 drive''s worth of I/O operations, not 6 drives'' worth. With 3 mirrors, you''d get 6 drives'' worth of reads and 3 drives'' worth of writes. Using raidz might get you slightly better read and write bandwidth, though. Scott