hi there, maybe this is a stupid question, yet i haven''t found an answer anywhere ;) let say i got 3x 1,5tb hdds, can i create equal partitions out of each and make a raid5 out of it? sure the safety would drop, but that is not that important to me. with roughly 500gb partitions and the raid5 forumla of n-1*smallest drive i should be able to get 4tb storage instead of 3tb when using 3x 1,5tb in a normal raid5. thanks for you answers greetings -- This message posted from opensolaris.org
On Wed, Jan 27, 2010 at 1:55 PM, Albert Frenz <yo at zockbar.de> wrote:> hi there, > > maybe this is a stupid question, yet i haven''t found an answer anywhere ;) > let say i got 3x 1,5tb hdds, can i create equal partitions out of each and > make a raid5 out of it? sure the safety would drop, but that is not that > important to me. with roughly 500gb partitions and the raid5 forumla of > n-1*smallest drive i should be able to get 4tb storage instead of 3tb when > using 3x 1,5tb in a normal raid5. > > thanks for you answers > > greetings > -- >3 drives is enough to make a raidz already but you can use slices...yes, i have a friend who did that. he had 2 1.5tb drives 2 1tb drives and a 2 tb drive so he made 2 raidz''s one with 5 1tb slices 1 with 3 500gb slices> This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20100127/0472abd7/attachment.html>
ok nice to know :) thank you very much for your quick answer -- This message posted from opensolaris.org
On Wed, Jan 27, 2010 at 10:55:21AM -0800, Albert Frenz wrote:> hi there, > > maybe this is a stupid question, yet i haven''t found an answer anywhere ;) > let say i got 3x 1,5tb hdds, can i create equal partitions out of each and make a raid5 out of it? sure the safety would drop, but that is not that important to me. with roughly 500gb partitions and the raid5 forumla of n-1*smallest drive i should be able to get 4tb storage instead of 3tb when using 3x 1,5tb in a normal raid5. >The only way you can use more than 3TB is if your RAID5 is not protecting data on different disks. By saying "500gb partitions", it sounds like you want to create a 9 column raid on 3 disks. The safety wouild definitely drop. It would drop so much that it''s not really buying you anything. The failure of any drive would mean loss of the data. So if that''s already true, why not just put all the disks in a pool and not mess with a raid? You''d get 4.5TB. Partitioning it into pieces and trying to put them all into a single RAID set just makes the setup more complex, probably slower, and almost no extra protection. -- Darren
Albert, On Wed, Jan 27, 2010 at 10:55:21AM -0800, Albert Frenz wrote:> hi there, > > maybe this is a stupid question, yet i haven''t found an answer anywhere ;) > let say i got 3x 1,5tb hdds, can i create equal partitions out of each and make a raid5 out of it? sure the safety would drop, but that is not that important to me. with roughly 500gb partitions and the raid5 forumla of n-1*smallest drive i should be able to get 4tb storage instead of 3tb when using 3x 1,5tb in a normal raid5. >Yes, it is possible to create partitions and configure it the way you mentioned. However, along with the drop in the safety, the performance will also drop because of potential seek delays. Thanks and regards, Sanjeev
Also write performance may drop because of write dache disable: http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide#Storage_Pools Just a hint, have not tested this. Robert -- This message posted from opensolaris.org