NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
Solved
Disc failure during expansion
Hi all. I have been running a ReadyNAS with 3 drives in for a while, (2+2+4 Gig respectively). I ended up with 3.6TB of capacity, and hit 80%+ full the other day. Accordingly, I put an 8Gig dr...
robinwatts wrote:
If I had an array with 4+8+8, could I safely add another 4TB drive later to get it to the maximum 16?
The usual guidance is that you can only add 8 TB (or bigger). Taking the expansion limits into account, that means upgrading the 4 TB to 8 TB.
Some experiments posted here show that OS-6 NAS would let you add a 4 TB (since there is a 4 TB already in the array). However, I don't know if OS 5 will allow that (though it is technically possible).
Under the covers, a 4+8+8 setup has two RAID groups - a 3x4TB RAID-5 group that covers all drives, and a 2x4 RAID-1 group that covers the two larger drives. These are assembled into one volume.
Adding a 2 TB drive requires that the 3x4TB group be split into two 3x2TB groups (followed by adding the new drive to one of those groups). XRAID won't split an existing group that way (and I don't think it can be done easily w/o data loss).
If I add another disc (say, another 8TB one), will that give me the expected amount of space? (i.e. at least 10TB redundant storage)?
Thanks.
The rule for single-redundancy XRAID (what you have) is "sum the disks and subract the largest".
So with 2TB + 4TB + 8TB + 8 TB you'll get 14 TB of redundant storage. The NAS reports TiB, so it will say ~12.7. (TB: 1000*1000*1000*1000 bytes; TiB:1024*1024*1024*1024 bytes).
If your 2 TB drive hadn't failed, you'd have had 2TB + 2 TB + 4 TB + 8 TB. That would have given you 8 TB (~7.3 TiB).
Thanks for that useful rule.
I've ordered a new 8TB drive.
I just want to be clear though - if I just power the array down, insert that new drive and power it back up, that'll give me the optimum setup?
The alternative (of connecting the new drive by USB, copying all the data across to it, factory resetting the NAS with the 3 drives I've already got, copying the data back on and THEN adding the 8TB drive) seems like a lot more faff...
Thanks.
robinwatts wrote:
I just want to be clear though - if I just power the array down, insert that new drive and power it back up, that'll give me the optimum setup?
You should be able to hot-insert the new drive into the failed drives slot. No need to power down, and there should be no need for a factory reset.
It is a good idea to back up the data though, just in case. RAID is a good thing, but it's not enough to keep your data safe (even when the array isn't degraded).
StephenB wrote:
robinwatts wrote:I just want to be clear though - if I just power the array down, insert that new drive and power it back up, that'll give me the optimum setup?
You should be able to hot-insert the new drive into the failed drives slot. No need to power down, and there should be no need for a factory reset.
OK, so what I feared would happen has happened.
I now have a NAS containing 2+4+8+8 TB of drives, telling me that 552.7GB of 3.6TB is free. My data is intact, but I'm getting a fraction of the storage I should. I've tried rebooting the NAS, but it never reshapes.
Please, what do I have to do to get the array to reshape?
Thanks,
Robin
P.S. Can anyone explain why I have md0, md1 and md2 setup please? Is this to be expected?
root@ReadyNAS:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md2 : active raid5 sda3[0] sdd3[3] sdc3[2] sdb3[4]
5846378112 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4] [UUUU]md1 : active raid1 sdd2[3] sda2[0] sdc2[2] sdb2[4]
524276 blocks super 1.2 [4/4] [UUUU]md0 : active raid1 sda1[0] sdc1[2]
4193268 blocks super 1.2 [2/2] [UU]unused devices: <none>
root@ReadyNAS:~# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Fri Oct 26 01:53:00 2012
Raid Level : raid1
Array Size : 4193268 (4.00 GiB 4.29 GB)
Used Dev Size : 4193268 (4.00 GiB 4.29 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistentUpdate Time : Wed Jul 5 00:04:20 2017
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0Name : 2CB05DBEAB2F:0
UUID : 34f72ac9:d360ca89:92f12084:939c7684
Events : 17017846Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
2 8 33 1 active sync /dev/sdc1
root@ReadyNAS:~# mdadm --detail /dev/md1
/dev/md1:
Version : 1.2
Creation Time : Fri Oct 26 01:53:00 2012
Raid Level : raid1
Array Size : 524276 (512.07 MiB 536.86 MB)
Used Dev Size : 524276 (512.07 MiB 536.86 MB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistentUpdate Time : Wed Jul 5 00:01:44 2017
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0Name : 2CB05DBEAB2F:1
UUID : 25472b3c:d3eaa178:89abf435:cce05bcf
Events : 287603Number Major Minor RaidDevice State
0 8 2 0 active sync /dev/sda2
4 8 18 1 active sync /dev/sdb2
2 8 34 2 active sync /dev/sdc2
3 8 50 3 active sync /dev/sdd2
root@ReadyNAS:~# mdadm --detail /dev/md2
/dev/md2:
Version : 1.2
Creation Time : Fri Oct 26 01:53:00 2012
Raid Level : raid5
Array Size : 5846378112 (5575.54 GiB 5986.69 GB)
Used Dev Size : 1948792704 (1858.51 GiB 1995.56 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistentUpdate Time : Wed Jul 5 00:03:30 2017
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0Layout : left-symmetric
Chunk Size : 64KName : 2CB05DBEAB2F:2
UUID : 237489f5:979f54be:b8d03e30:5717158c
Events : 23424Number Major Minor RaidDevice State
0 8 3 0 active sync /dev/sda3
4 8 19 1 active sync /dev/sdb3
2 8 35 2 active sync /dev/sdc3
3 8 51 3 active sync /dev/sdd3
NETGEAR Academy
Boost your skills with the Netgear Academy - Get trained, certified and stay ahead with the latest Netgear technology!
Join Us!
