how do I expand my apple raid

Question

I have an apple raid card in my Mac pro. I have set it up as a Raid 5 with Three internal 1.5 TB drives. I just replaced one with a 3tb drive. However the capacity did not increase. I looked at the manual and it tells me:Expanding a VolumeYou can use the command line to expand (add space to) an existing volume from the available space on the RAID set that hosts it. Expanding a volume doesn’t affect data already on the volume.To expand a volume:m Open Terminal and enter the following command:$ sudo raidutil modify volume --expand -n volume -s sizewhere volume is the name of the volume as shown by the raidutil list volumeinfocommand and size is the amount of space you want to add to the volume.For more information, see the raidutil man page.So I opened terminal and put in what it says. However terminal keeps getting stuck. below is what its saying. If anyone can tell me what I am doing wrong that would be awesome. I&#x27;m not sure why Apple put in such a round about expandtion any way. NYCretoucher-Remote:~ nisian$ sudo raidutil modify volume R1V1 --expand -n volume R1V1 -s size 700gRequired argument missing: &#x27;--rewrite&#x27;, or &#x27;--verify&#x27;, &#x27;--move&#x27;, &#x27;--expand&#x27;.usage: raidutil &lt;global-options&gt; modify volume &lt;required-arguments&gt; &lt;optional-arguments&gt;    global-options:        [--controller &lt;ControllerType&gt; | -c &lt;ControllerType&gt;]        [--terse | -t]        [--verbose | -v]        [--version | -V]    --expand | -e        required arguments:            --name &lt;VolumeName&gt; | -n &lt;VolumeName&gt;            --size &lt;SizeToExpandVolume&gt; | -s &lt;SizeToExpandVolume&gt;        optional arguments:            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;            --waitfortask | -W    --move | -m        required arguments:            --names &lt;VolumeName&gt; | -n &lt;VolumeName&gt;            --targetraidset &lt;TargetRAIDSetName&gt; | -t &lt;TargetRAIDSetName&gt;            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;        optional arguments:            --waitfortask | -W    --rewrite | -w        required arguments:            --name &lt;VolumeName&gt; | -n &lt;VolumeName&gt;        optional arguments:            --priority &lt;ServicePriority&gt; | -p &lt;ServicePriority&gt;            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;            --waitfortask | -W    --verify | -v        required arguments:            --name &lt;VolumeName&gt; | -n &lt;VolumeName&gt;        optional arguments:            --priority &lt;ServicePriority&gt; | -p &lt;ServicePriority&gt;            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;            --waitfortask | -WNYCretoucher-Remote:~ nisian$ sudo raidutil modify volume R1V1 --expandRequired argument missing: &#x27;--rewrite&#x27;, or &#x27;--verify&#x27;, &#x27;--move&#x27;, &#x27;--expand&#x27;.usage: raidutil &lt;global-options&gt; modify volume &lt;required-arguments&gt; &lt;optional-arguments&gt;    global-options:        [--controller &lt;ControllerType&gt; | -c &lt;ControllerType&gt;]        [--terse | -t]        [--verbose | -v]        [--version | -V]    --expand | -e        required arguments:            --name &lt;VolumeName&gt; | -n &lt;VolumeName&gt;            --size &lt;SizeToExpandVolume&gt; | -s &lt;SizeToExpandVolume&gt;        optional arguments:            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;            --waitfortask | -W    --move | -m        required arguments:            --names &lt;VolumeName&gt; | -n &lt;VolumeName&gt;            --targetraidset &lt;TargetRAIDSetName&gt; | -t &lt;TargetRAIDSetName&gt;            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;        optional arguments:            --waitfortask | -W    --rewrite | -w        required arguments:            --name &lt;VolumeName&gt; | -n &lt;VolumeName&gt;        optional arguments:            --priority &lt;ServicePriority&gt; | -p &lt;ServicePriority&gt;            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;            --waitfortask | -W    --verify | -v        required arguments:            --name &lt;VolumeName&gt; | -n &lt;VolumeName&gt;        optional arguments:            --priority &lt;ServicePriority&gt; | -p &lt;ServicePriority&gt;            --raidset &lt;RAIDSetName&gt; | -r &lt;RAIDSetName&gt;            --waitfortask | -WNYCretoucher-Remote:~ nisian$

Grant Bennet-Alder · Answer

I do not think you have any space to expand the Volume into unused space on the RAID set. I don&#x27;t think you will have any additional unused space on the RAID set until you upgrade THREE drives and re-make the RAID set in a larger size. You need to roll the data off to a backup (preferebaly two), swap in multiple comparable-sized larger drives, and re-make the RAID in a larger size.

Christopher Murphy · Answer

Three problems with this:1. My understanding is that the Apple RAID card doesn&#x27;t support drives larger than 2.2TB in size.2. RAID 5 requires all drives to be the same size in order for more space to be available, then the file system needs to be grown.3. The odds of an unrecoverable read error in the course of rebuilding a 3TB consumer SATA hard drive is actually rather high. 1 bit error in 1E14 is the most typical URE published by hard drive manufacturers for consumer SATA, and that translates to 11.4 TB, that is ever 11.4.TB of read, 1 bit error is expected. In the event of an unrecoverable read error, the reconstruction is halted. And a 3 disk RAID 5 means you&#x27;re reading 6TB of data to rebuild the 3rd drive. So your statistical chance of failure is in the vicinity of 50/50. Not good odds. Therefore you already need to consider RAID 6, or RAID 10 (or RAID 1 + linear which is growable by adding 2 disks of the same size at a time, which can be different sizes than the disks already in the linear array).