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Best file system for a file server serving only blu-ray ISO through Samba ? (no RAID)

post #1 of 6
Thread Starter 
Hi, I have a Samba file server running Ubuntu 12.04.
This server is on only when I want to watch a movie, and holds only my blu-ray rips in ISO format. I have a Synology NAS box for my other shared storage (music, photos and files) needs.

I Wake On LAN the server and remotely shut it off through SSH whenever I need it. The noisy beast lives in the mechanical room (it is a Norco 4020).

For many reasons, I decided not to use any form of real time RAID, but use snapraid using 2 parity disks (equivalent to a RAID6 setup). Currently, I have 6 3TB Seagate drives and 2 other for P and Q parity, but only the first 3 data drives have files at the moment.

I currently run ext4 on the system disk (60GB SSD) and xfs on all 8 hard drives. I initially selected xfs from old recommendations at the time I played with MythTV.

Since 3 of my 6 data drives are empty, I am thinking that it is still time to revisit my decision. (anyway, using snapraid I can always change as long as I have an empty disk).

So, for a file server having only Blu-ray ISO (20 to 50 GB files) what file system would you tend to use ? Performance is not much of an issue, my main concern is resiliency to unexpected power outage or other major HW failures (beside a single disk).

Thank you for sharing your wisdom !

Rudy
post #2 of 6
Resiliency: Power outage is not a major data-loss risk here. Lose power during playback, you have no data at risk. Lose power during a rip, you'd probably restart the rip from scratch anyways. Individual file corruption is a relatively minor issue, since you have an off-line backup (the original discs) and lots of practice restoring from that backup. Systemic file corruption is your biggest risk, since that carries the biggest penalty (labor and downtime reripping entire collection). The best defense against that is a well-tested filesystem.

Performance: With the boot-on-demand setup, it doesn't sound like you foresee serving lots of clients. No need for anything fancy.

In your shoes, I'd go with ext4 and forget about it. I might even consider ext2.

Another thing to think about is your raid setup. If the controller fails, what's your play? How long will it take to repair or replace it? How much more value does an 18TB RAID6 have over a 12TB RAID1 stack? You are covering yourself against 2 independent drive failures, but not all failures are independent (power surge, burst pipe, rack collapse, etc) In a 3-drive failure, you lose the whole collection with RAID6, but only 1/8th of the collection (on average) under RAID1.


What you are doing is basically providing a fast cache in front of slower storage (the original discs) This isn't like running a SAN that's holding OLTP databases, VM images, or encrypted data. In your scenario, partial data loss is tolerable. That changes the design.
post #3 of 6
Thread Starter 
Quote:
In a 3-drive failure, you lose the whole collection with RAID6
Actually, that's why I said no Raid in the thread's title.

Snapraid (see http://snapraid.sourceforge.net/) is a non real-time software solution providing the benefits of RAID5 or RAID6 data protection while keeping parity information on the P and Q hard drives and having the actual data on standard linux partitions, readable on any machine. People typically run an array check once a week or month and a partial sync on the file/directory/drive concerned by a rip or a change.

In other words, if I lose 3 disks in my 6+2 setup :
  • At worst all 3 are data disks so I still have 2 (now useless to me) valid PQ disks and 3 valid data disks.
  • At best, I lose P, Q and a data disk, leaving me 5 good disks.

This is far from losing a whole RAID6 array to a 3-disk failure...

Beyond total single or double disk failure, this also protects against long term bit rot.

So my question still stands : is there a better file system than xfs in my large file / low churn application ? Remember, system is on a separate ext4 SSD...

Thank you !
post #4 of 6
For large files, I always heard that JFS was better than XFS. XFS was reported to have file corruption problems, where that wasn't a problem with JFS.

It's my understanding that JFS is much better at deleting large files. If you are not going to delete your files, I don't know if there is any advantage to using it.

http://en.wikipedia.org/wiki/JFS_%28file_system%29
post #5 of 6
I've gotten corruption with XFS and JFS, but it consistently happens under certain circumstances with XFS, I've only had it once (and glad I had a backup) with JFS. JFS is lightning quick at deletions of large files, but XFS has been fast for me too.

- Just my 2 cents to add...
post #6 of 6
yes there is a better file system out there - native zfs but raid is required. In my case I'm using Freenas 9S with freebsd 9.0 stable. If you are happy with what you have and it works, then why worry about it. I used xfs before in a massive disk raid setup and just made sure I had a battery backup that would shut off the computer cleanly on a power failure before the battery was drained and never had the first issue. I'm not sure on snapraid but with every other software based raid I have had zero issue with hardware failures as the disks can just be put into a system and everything is fine.
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