Personally, I did 2 6-disk raidz2 vdevs in my pool with Samsung 1.5TB drives. With these large drives, I don't trust single parity, and I wanted a little more performance than a single vdev would be able to provide. While it would certainly saturate a single gigabit link, I do a fair bit of processing on the machine itself and faster disk I/O helps there. There is also the future possibility of doing bonded links if I buy a managed switch, so I would have 2 or more gigabit links to this server. Probably unnecessary, but nice to have the option.
>From reading, it sounds like a raidz is about as fast as the slowest drive in >the array. Stripping more than one raidz together is about the same as adding >the performance of the arrays. As a rough idea it seems to work. So if you >don't mind being I/O bound to the speed of a single drive, go for it. >Personally, I wouldn't trust even raidz2 with 14 1TB drives. I'd go to raidz3. The other thing to consider for a home server, is that to upgrade storage space on this machine you have to do a full vdev at once. So if you made a single 14 disk raidz, you have to upgrade ALL 14 drives to see any additional space in the array. With the 2 array setup, you can upgrade 7 drives at a time, and the old drives become cold spares, or can be put into an older machine for backups. That was a big reason I went to 2 arrays, it's MUCH easier to get funding for 6 drives than 12. Yes, I "lost" 4 disks to parity. However, I now have 8 disks of very secure, redundant data. I found that to be a reasonable trade for not having to rip all those CDs, DVDs and BDs again. :) I also used my old Linux fileserver parts to build a backup machine for really important data that I intend to move off-site here soon using CrashPlan to back up to it. Keep in mind that with the large drives we have today, replacing one is going to take many hours of heavy I/O. And if another drive fails while you're doing that... bye-bye data. There were some great articles posted in the ZFS list a while back about the time to data loss with various parity levels. I found it helpful in deciding my strategy. Remember to scrub periodically. I have it set in cron for once a month. I just log into the server and check with "zfs status" to make sure things are working well still. -- This message posted from opensolaris.org _______________________________________________ opensolaris-help mailing list [email protected]
