We have a server with an Adaptec 5805 RAID 1 array, with two SAS 146GB disks. We need more space on this server.

Is it possible to hot-replace each 146GB HD with a 300GB HD, and let the controller reconstruct the array after each disk change? Is the new space left automatically visible after the second disk change?

  • 2
    Thou shalt not accept the wring answer.:) – sjas Oct 26 '14 at 0:46

That won't work sorry - if you removed the first disk and replaced it with the larger one that disk would be setup by the controller as through it were a 146GB disk not a 300GB disk and the same would occur when you replaced the second smaller disk.

That controller does support RAID-level migration however so you could add one of the new disks as a third member of a RAID 5 array but it would still only add 146GB to that array.

  • absolutely wrong. adaptec has online capacity expansion. after first drive will be replaced, raid 1 array will be reconstructed, then same can be done with second drive, and finally, array will be expanded. – GioMac Sep 1 '13 at 9:06
  • Exactly. That said - it does not expand the RAID array automatically, this is a manual process. But it is doable - so another one of those "Accepted but Wrong" answers, sadly. – TomTom Sep 1 '13 at 11:27

You can definitely do this.

I replaced a faulting 1TB disk with a 2TB disk; it did rebuild the array, then I replaced the non-faulting 1TB disk with another 2TB disk. After the second rebuild, you need to go in and adjust the device size in the RAID manager software (which you can't do whilst the rebuilds are taking place).

The RAID manager software I used was "Adaptec Storage Manager" --> Actions "Expand or Change Logical Drive". Then I increased the size and let it reconfigure the device.

The reconfiguring started at 50% and took a very long time, but it eventually finished.

After that, I had to increase the file system (NTFS on W2K8 server), but I had to rescan the disks first (diskmgmt.msc). After increasing the NTFS size to take up all the extra space (which shows as unallocated space), the server was somewhat non-responsive, a reboot fixed this and everything is working fine now with the file system seeing the new full capacity.


Yes, it will be.

Adaptec doesn't care about disk size - it supports and works with partitioning (segments). Adaptec supports live migration and kernel can recognize block device size changes. You should replace disks one-by-one and rebuild same size array, then expand array.

And that's all you need to do.

You will see kernel message after:

[ 3996.863384] sdd: detected capacity change from 2003828736 to 6700382873 

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