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Using Raid5 with six disk, but only getting 21.54TB

PostPosted: Sun Dec 29, 2019 1:25 pm
by simmiv
Hi,
I'm just wondering if I've done something wrong.. I had 4 x 6TB WD RED NAS drives in a raid 5 configuration.. This gave me 16.4TB of usable space. I recently added 2 x 6TB WD RED NAS drives and added them to the existing Raid 5, expecting to have 27TB available. However, it only shows 21.54TB.. When adding I ticked both drives and after 48 hours of rebuild, this is the result. According to Raid5 calculators I should have 27TB, not just over 21TB.. Any ideas as to why this occured, or what I have to do to reclaim more free TB? I'm using AS6210T with 10 drive bays and the latest version of the ADM..

Re: Using Raid5 with six disk, but only getting 21.54TB

PostPosted: Sun Dec 29, 2019 7:59 pm
by Ubuntux
Hmm.. Id say you should have 30 TB. 6 * 5 = 30 TB (i know you have 6 disks, but -1)

See their RAID calculator: https://www.asustor.com/service/RAID_calculator

Have you tried to click on the expand capacity? Seems like its clickable...

Re: Using Raid5 with six disk, but only getting 21.54TB

PostPosted: Mon Dec 30, 2019 6:54 am
by simmiv
Yes, I have tried numerous times to click expand capacity. It simply pops up the rotating circles and Applying for a few seconds and then goes away without any change.. I tried shutting the NAS down and restart.. When I did that it came up and seemed to be stuck on "Booting Storage Please Wait". After waiting 10 minutes I shut it down again and took out each drive and reinserted and tried again with the same results. I then simply turned it off as the drives seemed a bit hot. After half an hour I turned it on again and an hour later it suddenly came back again and seems to be working fine, apart from the disk space being less than it should be. It appears that if it seems stuck with "Booting Storage Please Wait" it could take up to an hour to come good..

I've lodged a ticket with Asustor support, so I'll see what they think..

Re: Using Raid5 with six disk, but only getting 21.54TB

PostPosted: Mon Jun 08, 2020 9:28 am
by simmiv
After a long time, I've finally been brave enough to both update the ADM and kill the Raid 5 volume and it's now rebuilding.. It's rebuilding with the capacity of 27.16 TB.. So it looks like it will be the right size. I learned from this that when you add a drive or drives to your Raid 5, do it drive by drive.. Don't add them all at the same time.. The risk is that the volume will not be expanded to it's fullest capacity. It's pretty bad as you have to wait a long time for the added drive to replicate each time. I'm assuming this is a bug in the volume manager software and there is no fix. Asustor support couldn't help or didn't want to find out why this would occur, so they just told me to re-build the volume again.