[Tfug] HDD size and RAID queries

[Dean Jones]

On Wed, May 8, 2013 at 7:27 AM, Zack Williams <zdwzdw at gmail.com> wrote:

>
> On Wed, May 8, 2013 at 4:49 AM, John Gruenenfelder <jetpackjohn at gmail.com>wrote:
>
>> The argument to ditch RAID-5 in favor of RAID-6 is entirely based on
>> probabilities and the likelyhood of encountering an unrecoverable error
>> while
>> rebuilding an array.  Am I actually in this realm with these drive sizes?
>>
>
> Generally that threshold is something in the 1-3TB disk size for SATA,
> depending on the calculations used and how much risk you want to take
> during a build/rebuild.
>
> For long term reliability, I'd look at ZFS or similar filesystems that
> checksum the entire on-disk data structure and can verify ("scrub") that
> the data you have is actually intact.  I basically don't trust any data I
> have that isn't checksummed in some manner (either on-disk, by version
> control, or by backup software).
>
>
I second what Zack says, mostly the ZFS recommendation. The era of offline
file system checks, and blindly trusting the reads from a FS should be
over. I would shy away from BTRFS just yet.

My threshold at work for ditching RAID5 is if the base drives are over
1TB.  Past that size rebuild times start getting extreme. So everything is
either RAID6 for capacity or RAID10 for performance.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://tfug.org/pipermail/tfug_tfug.org/attachments/20130508/3749b76c/attachment-0002.html>