Sanest way to swap out dying 12x1.5TB drives with 5x4TB drives?

[EGOvoruhk]

Here's the break down:

 

I have 25 drives total (23 data, 1 parity, 1 cache) at roughly 90-95% array capacity. 12 of those drives are all showing signs of aging (old Seagate 1.5TBs). I recently added 1x4TB drive to the array and copied the data of 3x1.5TB drives to it. I now have 3x1.5TB drives with no data, and 9x1.5TB drives with data that I would like to get off ASAP. Problem is, I have no more slots to add the drives for data swapping, since 23 data drives is the unRAID max. What's the safest way to go about migrating everything?

 

Ideally, I'd like to avoid doing a New Config and just physically removing the drives beforehand, as that will bring the parity down while it rebuilt. I would also have to run it a total of 2 more times, once I started to gain open disk slots. I haven't had any issues yet with the parity yet, but that's too much time without it for my taste, so I'll look for another way...

 

Is there another way?

 

As of now, my current thinking is that I'm a few months out from having my second larger server online, and I'll just migrate all the data to there, but that leaves me unable to put anything new on my unRAID server until then, at least not without putting it on a drive it keeps warning me about 

 

Any suggestions, experience, comments?

Thanks in advance

[trurl]

Get smart reports from all drives. Choose which ones to replace based on age or issues.

 

Rebuild one of these onto a new larger drive. Repeat for 5 drives.

 

Copy files from other small drives to free space on larger drives.

 

When done will all small drives then remove, do new config without them, and rebuild parity.

 

It is also possible to zero a drive with it in the array, remove it, and trust parity in the new config, but that is more complicated, requires working at the command line where you might make mistakes, and would ultimately take a lot more time. There are several threads about this. Here is one.

[Keyser Soze]

How about emptying your current cache drive, set the drive you want to remove as new cache and activate mover.

[SSD]

What size is your current parity? What drive size are you planning for the replacements? What would you like your final array configuration to look like after the replacements?

 

Do you have a spare or makeshift server that could be leveraged for the migration?

 

If possible, I would stand up a temporary server with the replacement disks, and copy the data from your 1.5T drives to newly precleared and formatted disks (no parity yet) over the LAN. Do an md5 compare with the source disks. Then pull all the old drives from the array, add the new drives from the temporary server, do a new config, and build parity. The old 1.5T drives are a partial backup.

 

If you have an empty new disk, backup your memory stick with array stopped before removing the old disks. Use the new disk as parity and add your current parity as a data disk. When you build the new parity, do no writes to the array and do not format the old parity disk. If you do this, and a drive fails during the parity build, you can reconstruct it with some instructions I can provide.

[trurl]

How about emptying your current cache drive, set the drive you want to remove as new cache and activate mover.

Setting the drive as cache means setting it as no longer in the array, so would require a new config and invalidate parity. A new config would eventually be necessary the way I suggested also, but not with each removal.

[garycase]

At this point you've only got 9 drives to empty = 13.5TB max data ... so 3 or 4 4TB drives will do it.

 

IF you currently have good parity (Run a check if it's not very current), there are two ways you could proceed:

 

(1)  Do do as trurl suggested => simply swap a 4TB drive for ONE of the drives;  then repeat that for a 2nd; and again for a 3rd; and, if needed, a 4th.  At that point you'll have plenty of space to copy all of the data from the remaining drives.    After you've got all the data off of the final few 1.5TB drives, do a New Config without them; and then do a parity sync.  You'll now have a few spare slots; and no more 1.5TB drives 

 

or

 

(2)  Remove ALL of the 1.5TB drives;  add as many 4TB drives as you want (at least 4, since that guarantees enough space for the 9 1.5TB units you removed); do a New Config, and let the new parity sync finish.  As always after a new parity sync, you should run a parity check to confirm all went well.

 

Now, one-at-a-time, copy the data from the 1.5TB drives to the array ... either over the network from another PC; or via a USB connection to the server.

 

 

Note that #1 requires running "at risk" several times -- during every rebuild and during the parity sync after the New Config.    #2 only runs "at risk" during the parity sync, but also has a bit of risk that should any of the 1.5TB drives fail during the copies there's no fault-tolerance for that drive.    Note that if a 1.5TB drive other than the one being rebuilt fail in #1 you'd have the same problem.