5 ms·

You can remove each disk and replace with a bigger one (wait for rebuild each time), and if you set autoexpand, the pool will resize afterwards.

by herf 12y ago

voltagex_ 12y ago
Doing some more reading, this sounds like it "degrades" the array each time and could be risky. Other replies to my comment seem to suggest it can't be done.
- takeda 12y ago
  I believe there are no problems with your scenario, there's zpool replace command which does this: zpool replace [-f] pool device [new_device] Replaces old_device with new_device. This is equivalent to attaching new_device, waiting for it to resilver, and then detaching old_device. The size of new_device must be greater than or equal to the minimum size of all the devices in a mirror or raidz configuration. new_device is required if the pool is not redundant. If new_device is not specified, it defaults to old_device. This form of replacement is useful after an existing disk has failed and has been physically replaced. In this case, the new disk may have the same /dev path as the old device, even though it is actually a different disk. ZFS recognizes this. -f Forces use of new_device, even if its appears to be in use. Not all devices can be overridden in this manner.
  - mosselman 12y ago
    Thanks for pointing this out. I still don't know how to see all of this in a home NAS context however. It would be really great if someone could explain. Lets say I have 6 SATA ports. I have 4 drives that I collected from various computers that I now want to unify in a home built NAS: A. 1TB B. 2TB C. 4TB D. 1TB E. -empty- F. -empty- Now all my drives are full and I want to either add a disk or replace a disk; How do I: 1. replace disk A. with a 4TB disk 2. add a 4TB disk on slot E.
    - enneff 12y ago
      1. connect 4T disk to F, "zpool replace pool A F" 2. connect 4T disk to E, "zpool add pool E" Where A, E, and F are virtual devices (vdevs) provided by your OS. On my FreeBSD system they are da0, da1, etc.
      - mosselman 12y ago
        Thanks. There are a lot of complicated articles spread around which make ZFS seem very hard for some reason. This seems fine.
- lmm 12y ago
  As long as you have room to connect one extra drive there's no "degrading" - add new disk, zfs replace, remove old disk, repeat. I've done this and it worked, and I've had the new disk fail partway through and not had to spend any time resilvering, so I don't think there's any degrading. (In any case you're certainly in no worse a situation than you would be if you had a single-drive failure. If you're worried about having a second drive fail while you're replacing a disk after a failure, use raidz2). Obviously if you only have 4 drive slots and have to remove a disk to replace it then you're going to have less redundancy while you're in the process of doing the replacement.

You can remove each disk and replace with a bigger one (wait for rebuild each time), and if you set autoexpand, the pool will resize afterwards.

by herf 12y ago

You can remove each disk and replace with a bigger one (wait for rebuild each time), and if you set autoexpand, the pool will resize afterwards.

voltagex_ 12y ago

Doing some more reading, this sounds like it "degrades" the array each time and could be risky. Other replies to my comment seem to suggest it can't be done.

takeda 12y ago
I believe there are no problems with your scenario, there's zpool replace command which does this: zpool replace [-f] pool device [new_device] Replaces old_device with new_device. This is equivalent to attaching new_device, waiting for it to resilver, and then detaching old_device. The size of new_device must be greater than or equal to the minimum size of all the devices in a mirror or raidz configuration. new_device is required if the pool is not redundant. If new_device is not specified, it defaults to old_device. This form of replacement is useful after an existing disk has failed and has been physically replaced. In this case, the new disk may have the same /dev path as the old device, even though it is actually a different disk. ZFS recognizes this. -f Forces use of new_device, even if its appears to be in use. Not all devices can be overridden in this manner.
- mosselman 12y ago
  Thanks for pointing this out. I still don't know how to see all of this in a home NAS context however. It would be really great if someone could explain. Lets say I have 6 SATA ports. I have 4 drives that I collected from various computers that I now want to unify in a home built NAS: A. 1TB B. 2TB C. 4TB D. 1TB E. -empty- F. -empty- Now all my drives are full and I want to either add a disk or replace a disk; How do I: 1. replace disk A. with a 4TB disk 2. add a 4TB disk on slot E.
  - enneff 12y ago
    1. connect 4T disk to F, "zpool replace pool A F" 2. connect 4T disk to E, "zpool add pool E" Where A, E, and F are virtual devices (vdevs) provided by your OS. On my FreeBSD system they are da0, da1, etc.
    - mosselman 12y ago
      Thanks. There are a lot of complicated articles spread around which make ZFS seem very hard for some reason. This seems fine.
lmm 12y ago
As long as you have room to connect one extra drive there's no "degrading" - add new disk, zfs replace, remove old disk, repeat. I've done this and it worked, and I've had the new disk fail partway through and not had to spend any time resilvering, so I don't think there's any degrading. (In any case you're certainly in no worse a situation than you would be if you had a single-drive failure. If you're worried about having a second drive fail while you're replacing a disk after a failure, use raidz2). Obviously if you only have 4 drive slots and have to remove a disk to replace it then you're going to have less redundancy while you're in the process of doing the replacement.