RAID 6 vs RAID 10 - LFF - Winchester - Synology Backup Device

  • So this conversation is back again 😖

    For a backup device, that has yet to be ordered, the boss and vendor really would prefer to use RAID 6. I'm not against this, but this is the sole backup target for use "today". Some point in the future we would be pushing a copy of this offsite so we're in the 3-2-1 rule.

    I was balked at when saying we want a minimum of 40TB of backup space (5 fulls worth of storage allocated today) with "you're adding cost that I wasn't aware of"

    Which whatever, no I'm not. Had that conversation already.

    Being the primary device, onsite, we're looking at the Seagate 4TB NAS drives and the Synology RS2416+.

    Is it unreasonable to really push for the RAID10 configuration for the on-site device? Should I just let this horse go?

  • Does it need the gains of RAID10?

  • Service Provider

    RAID 10 is almost always unreasonable for backups larger than four physical drives in size. (Read: larger than 12TB.) Backups are simply not that important 99% of the time. Unless you have specific reasons why RAID 6 doesn't do the job (mostly around performance or that these are not backups but archives and more critical than the term backup implies) then RAID 10 should pretty much only be a passing mention but the cost/risk analysis for backups says that RAID 6 is almost always the best choice.

  • Okay, so RAID 6 is the go to solution here.

    I was looking at the scenario of cost / reliability, not cost / performance & capacity.

    If RAID 6 suffices for the rest of you for an XO/Shadow Protect backup target, I'll agree, but I just don't trust the MSP with a lot that comes that way.

  • Service Provider

    RAID 6 or, at least scale, RAID 60. 40TB is not so large, though. Only about 12 drives, so way below the RAID 60 threshhold (which is somewhere around 20 - 26 drives.)

  • Service Provider

    Remember that this is backup. So if the backup system fails you have options like...

    • Taking a new backup from the live systems.
    • Offlining the limping array and taking a full backup of it before attempting a restore
    • Doing a backup/restore rather than an array recovery

    All of these things make RAID 6's risks minimal. This isn't the only copy of anything, it's a backup. And it is not subject to availability risks (at least not in the way that live data is) so things that cause availability issues are not significant.