Re:I made a new backplane for my consumer NAS
by toast0 on Tuesday April 30, 2024 @12:42PM
(#40213045)
Well, the person I was responding to asked for 6x SATA. So there's that.
Personally, I like 6x SATA for a couple reasons. One is my case has sleds for 6 drives :P. The other is I run two servers with 2x mirrors as the main storage (they backup each other and are in different buildings although on the same site, which gives me a little redundancy, but not much); I've done an upgrade once from 4 tb to 10 tb, so my case with 6 sleds now has the main 10tb mirror array, and a playspace for less important stuff that I can figure out how to use over time; currently I've got it split up between 50% of each disk used individually for tv recordings, and the other 50% as a raidz2 to hold dvd's i've ripped and fanedits.
When I upgrade/replace the main mirrors, I may update the other server to have more slots, and then it can have a 4x 10tb playspace.
> Yes, you lose a little resilience compared to RAIDZ2, but RAID is just a HA solution, not a backup solution, no matter how fancy you make it. And a RAIDZ2 gradual-upgrade by replacing disk after disk is just horrible.
I haven't done it, so I'm not disagreeing... I'm assuming the main objection is it takes a long time, and the secondary objection is the system has a lot of disk contention while it's in progress. I'd probably address the takes a long time by just planning to do one disk every other week. That means it's a two month process, but it also means that the drives in the system have a two month offset on usage time; a lot of drive array failures are due to correlated failures, and offsetting the power on time can help. If all of your disks are likely to fail when their power on counter rolls over, it's nice if you have two weeks between failures --- that should hopefully be plenty of time to replace disks before you lose the data.
Ordering disks over a two month period may also help avoid getting all disks from the same batch; but sometimes it's better to order all at once for pricing, so that's mixed.
If you do have extra SATA ports, you might be able to do a replace while both the old and new disk are available... I'm not sure if that helps the process or not; it won't reduce the amount of writes to the new drive, but maybe it helps with disk contention during the process?
Personally, I like 6x SATA for a couple reasons. One is my case has sleds for 6 drives :P. The other is I run two servers with 2x mirrors as the main storage (they backup each other and are in different buildings although on the same site, which gives me a little redundancy, but not much); I've done an upgrade once from 4 tb to 10 tb, so my case with 6 sleds now has the main 10tb mirror array, and a playspace for less important stuff that I can figure out how to use over time; currently I've got it split up between 50% of each disk used individually for tv recordings, and the other 50% as a raidz2 to hold dvd's i've ripped and fanedits.
When I upgrade/replace the main mirrors, I may update the other server to have more slots, and then it can have a 4x 10tb playspace.
> Yes, you lose a little resilience compared to RAIDZ2, but RAID is just a HA solution, not a backup solution, no matter how fancy you make it. And a RAIDZ2 gradual-upgrade by replacing disk after disk is just horrible.
I haven't done it, so I'm not disagreeing... I'm assuming the main objection is it takes a long time, and the secondary objection is the system has a lot of disk contention while it's in progress. I'd probably address the takes a long time by just planning to do one disk every other week. That means it's a two month process, but it also means that the drives in the system have a two month offset on usage time; a lot of drive array failures are due to correlated failures, and offsetting the power on time can help. If all of your disks are likely to fail when their power on counter rolls over, it's nice if you have two weeks between failures --- that should hopefully be plenty of time to replace disks before you lose the data.
Ordering disks over a two month period may also help avoid getting all disks from the same batch; but sometimes it's better to order all at once for pricing, so that's mixed.
If you do have extra SATA ports, you might be able to do a replace while both the old and new disk are available... I'm not sure if that helps the process or not; it won't reduce the amount of writes to the new drive, but maybe it helps with disk contention during the process?