A few quick notes. 2540's first 12 drives are extremely fast due to the fact that they have direct unshared connections. I do not mean that additional disks are slow, I want to say that first 12 is extremely fast, compared to any other disk system.
So although it's a little bit expansive but it could be a lot faster to add a second 2540 , than adding a second drive expansion. We generally use a few 2540's with 12 drives running in parallel for extreme performances. Agin with the additional disk tray 2540 will still perfom quite good, for the extreme performance.... Mertol Ozyoney Storage Practice - Sales Manager Sun Microsystems, TR Istanbul TR Phone +902123352200 Mobile +905339310752 Fax +902123352222 Email [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ross Sent: Sunday, August 31, 2008 12:04 PM To: zfs-discuss@opensolaris.org Subject: Re: [zfs-discuss] Proposed 2540 and ZFS configuration Personally I'd go for an 11 disk raid-z2, with one hot spare. You loose some capacity, but you've got more than enough for your current needs, and with 1TB disks single parity raid means a lot of time with your data unprotected when one fails. You could split this into two raid-z2 sets if you wanted, that would have a bit better performance, but if you can cope with the speed of a single pool for now I'd be tempted to start with that. It's likely that by Christmas you'll be able to buy flash devices to use as read or write cache with ZFS, at which point the speed of the disks becomes academic for many cases. Adding a further 12 disks sounds fine, just as you suggest. You can add another 11 disk raid-z2 set to your pool very easily. ZFS can't yet restripe your existing data across the new disks, so you'll have some data on the old 12 disk array, some striped across all 24, and some on the new array. ZFS probably does add some overhead compared to hardware raid, but unless you have a lot of load on that box I wouldn't expect it to be a problem. I don't know the T5220 servers though, so you might want to double check that. I do agree that you don't want to use the hardware raid though, ZFS has plenty of advantages and it's best to let it manage the whole lot. Could you do me a favour though and see how ZFS copes on that array if you just pull a disk while the ZFS pool is running? I've had some problems on a home built box after pulling disks, I suspect a proper raid array will cope fine but haven't been able to get that tested yet. thanks, Ross -- This message posted from opensolaris.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
