Advice on replacing ReadNAS Pro 6 with 2x 4 Bay ReadyNAS boxes.
I have a ReadyNAS Pro 6 with 6 x 3TB drives in Raid X which I think gave me 12TB of usable storage.
My ReadyNAS recently suffered some sort of corruption that made the volume inaccessible. This has made me realise that I need to have a more robust plan to backup data. The one box is great to protect against individual drive failures but not loosing the whole raid away via software corruption.
Luckly, I did have all my really important data backed up, so the stuff I have lost is inconvenient but not the end of the world.
so what I am thinking is buying two 4 bay ReadNAS boxes. One will be the N in daily use and the other will be backup of the main box. I seem to recall built in functionality that enables ReadyNAS boxes to backup to another ReadyNAS?
with that in mind I'm looking at getting a ReadyNAS 314 as the main box and a ReadyNAS 204 as the backup. I will put 4x 3TB drives in each for starters but plan to upgrade to larger dives over time.
what will be the usable space on each box with the 3TB drives?
When I add a larger drive, will the extra space be available or will I have to wait until all drives are larger? I seem to recall something about the raid being based on the smallest drive?
Re: Advice on replacing ReadNAS Pro 6 with 2x 4 Bay ReadyNAS boxes.
The limitation where we used the capacity of the smallest disk was for X-RAID on our legacy Sparc boxes. We discontinued the last of those several years ago now.
On newer boxes than that we use X-RAID2. With the default single-redundancy (uses RAID-5 with three or more disks) you would get the capacity of your drives summed minus the capacity of the largest disk minus some overheads.
With X-RAID2 dual-redundancy (uses RAID-6 and thus requires a minimum of four disks) you would be limited to the capacity of the 4th largest disk (as a RAID-6 layer requires a minimum of four disks)
Re: Advice on replacing ReadNAS Pro 6 with 2x 4 Bay ReadyNAS boxes.
As mdgm says, the capacity rule is "sum the drives and subtract the largest". 6x3TB with default XRAID would give you a 15 TB volume. The Pro-6 reports that as 13 TiB (but it uses a TB label, which is confusing). (1 TiB = 1024*1024*1024*1024 bytes, 1 TB = 1000*1000*1000*1000 bytes).
-You might consider starting with 3x4TB instead (if that leaves you enough free space). That costs about the same, and gives you an expansion slot for later.
-OS 6.6.0 has an interesting new backup method you might look into - that would require two RN314 though.
I recommend getting NAS-purposed disks (WDC Reds, Seagate VNs), or enterprise. I don't recommend desktop drives.
Re: Advice on replacing ReadNAS Pro 6 with 2x 4 Bay ReadyNAS boxes.
My plan is to reuse my current disks to cut down the initial costs. I have 1 spare 3TB disk plus the 6 in my Pro, so I was planning to add 1 4TB to the main box to start with.
