On 03/05/2015 08:48 AM, Alex Regan wrote:
Hi, I have a fedora20 system acting as a backup server, and I've exceeded its capacity. I'd like to build a bigger one, probably using fedora21. I currently have a 3TB backup system using five 1TB disks in RAID5. Restore times in case of disk failure are already exceedingly long, so I'd like to consider another method of providing redundancy, and would like suggestions.
Five 1TB disks in a RAID5 should give you about 4TB usable storage. Are you sure you're not using RAID6 (two parity drives)?
I'd like to have 6TB of usable space using 2TB disks.
Four 2TB drives in a RAID5 or five 2TB drives in a RAID6 would give you this. I'd vote for the RAID6.
Is ext4 still best for this?
BTRFS or (gulp!) XFS might be better, although ext4 would work.
Some RAID variant or is there something better?
The bigger the partition (LUN, PV, LV, whatever), the longer the recovery times are in case of a disk failure. I run a number of very large storage platforms (>500TB) and as soon as any LUN hits the 1TB mark, I immediately go to RAID6, simply because there is a possibility that a second drive may go bad while the first one is rebuilding. RAID6 gives me that cushion. There are a couple of things I do: 1. I prefer using hardware RAID over software RAID. More expensive, but I feel it's more reliable. 2. I like using hot-swappable drive arrays so drive replacement is easy. 3. I like having my drives from different manufacturing batches because (and this is just based on experience--I can't prove it) when one drive from a batch dies, another from that same batch with the same number of running hours on it will likely die soon.
Are there any NAS projects that may be beneficial?
The underlying technology of the drive arrays will be the same in a NAS as a SAN. It's only the access method that's different and the fact that some attributes (permissions, ACLs, etc.) may not be translatable between the native system and a NAS. Generally they are translatable on a SAN (and I include raw SAN LUNs shared via iSCSI in this) simply because it is a directly coupled system and uses the host's native filesystems. Your mileage may vary and I'm sure others on the list have equally strong opinions. ---------------------------------------------------------------------- - Rick Stevens, Systems Engineer, AllDigital ricks@xxxxxxxxxxxxxx - - AIM/Skype: therps2 ICQ: 22643734 Yahoo: origrps2 - - - - To err is human. To forgive, a large sum of money is needed. - ---------------------------------------------------------------------- -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
