[mythtv-users] RAID suggestions?

David Brodbeck gull at gull.us
Wed Nov 7 01:05:05 UTC 2007

On Nov 6, 2007, at 4:20 PM, Bruce McKenzie wrote:
> Is xfs or jfs safe over NFS? (I will not go back to Reiser; too  
> burned) Last I
> checked xfs was not as stable as ext3...

XFS is stable as long as you aren't using 4K stacks.  If you are, and  
you're stacking up block device layers (LVM, RAID, etc.), you may run  
into problems.

I don't know of any problems with NFS and specific filesystems.   
(Except maybe ones like vfat, that violate basic assumptions about  
UNIX filesystems.)  I NFS export an XFS filesystem with no trouble.

> Are there appropriate export/mount options? I currently use:
> # fstab on file server:
> /dev/VG01/LV01          /vault1         ext3    defaults,noatime

That seems fine for ext3.  For xfs, I like to add "allocsize=512m".   
This seems to reduce fragmentation on drives that are constantly  
close to full.

> # /etc/exports:
> /vault1,no_root_squash,rw,no_subtree_check)

async is sort of "living dangerously," but it does provide a  
significant speed boost in some circumstances.  Probably worth it for  
a video drive.

> # fstab on MythBE:
> filer:/vault1 /mnt/vault1 nfs
> soft,intr,bg,tcp,rsize=32768,wsize=32768,nfsvers=3,actimeo=0

'bg' can be a double-edged sword.  If MythTV starts before the NFS  
mount completes you can end up with video recordings on the local  
disk, under the mount point.  If you have to use bg you might want to  
think about putting a test in your mythbackend startup script to make  
sure the video directory is mounted before you let mythbackend start.

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