3 ms·

I’m incredibly interested in this. I run multiple 60+ disk arrays, but never with enough of a budget for the extra servers required for a better distributed sys

I’m incredibly interested in this. I run multiple 60+ disk arrays, but never with enough of a budget for the extra servers required for a better distributed system. Basically these are single large JBODs that store large genomics data. (Cheap and big are the only priorities, speed is a distant third). Right now, I use ZFS with multiple raidz2 or raidz3 vdevs with a number of hot spares waiting to take over. Resilvering can take a day for a 4TB disk. I’m terrified how long a 12TB disk will take (hence the move to raidz3). Disk loss is a normal fact of life, and it’s something we prepare for. But this would help me sleep better at night. I’m seriously excited about this and I’m definitely the target audience for this.

secabeen 6y ago
I'm in the same boat, but I don't run hot-spares. If a drive fails, I want a human in the loop before a resilver begins. Ive seen too many communication/cabling errors over the years, and I'd rather try to confirm the root cause before assuming that the problem is a bad disk.
- rsync 6y ago
  I really like this line of thought and I think your instinct is very good here. Remember - if you are in the middle of a potentially failing array, every single bit of parity data is pure gold and if you fail out a drive, that drive worth of parity is gone forever. So if you fail out a drive but it was actually weird bus errors getting spammed by some other drive that is actually failing, now you're in trouble ... While on the topic, in filesystem emergencies, don't forget the ability to mount, and even run, read-only. Your filesystem might be puking on mount and backing you into a corner, but perhaps if it were mounted read-only ...
rsync 6y ago
Even with 16TB disks I would not worry about 12 or 15 disk vdevs running in raidz3. Which is to say, beat the shit out of the disks before deploying them[1] to weed out early failures, then aggressively fail them out at the first sign of trouble[2]. We don't use hot spares - we just very aggressively pull drives that give us any meaningful smart errors ... [1] perhaps with the badblocks tool ... [2] smartctl

secabeen 6y ago

I'm in the same boat, but I don't run hot-spares. If a drive fails, I want a human in the loop before a resilver begins. Ive seen too many communication/cabling errors over the years, and I'd rather try to confirm the root cause before assuming that the problem is a bad disk.

rsync 6y ago
I really like this line of thought and I think your instinct is very good here. Remember - if you are in the middle of a potentially failing array, every single bit of parity data is pure gold and if you fail out a drive, that drive worth of parity is gone forever. So if you fail out a drive but it was actually weird bus errors getting spammed by some other drive that is actually failing, now you're in trouble ... While on the topic, in filesystem emergencies, don't forget the ability to mount, and even run, read-only. Your filesystem might be puking on mount and backing you into a corner, but perhaps if it were mounted read-only ...

rsync 6y ago

Even with 16TB disks I would not worry about 12 or 15 disk vdevs running in raidz3. Which is to say, beat the shit out of the disks before deploying them[1] to weed out early failures, then aggressively fail them out at the first sign of trouble[2]. We don't use hot spares - we just very aggressively pull drives that give us any meaningful smart errors ... [1] perhaps with the badblocks tool ... [2] smartctl