[mythtv-users] Storage best practices in 2017

[Simon Hobson]

Joseph Fry <joe at thefrys.com> wrote:

> Personally, I wouldn't mess around with RAID, LVM, ZFS, etc.  Buy as much storage as you need for online use, and backup important data frequently to an offline drive that you store in a media safe (unless you can put a NAS at a friend/neighbors house and do offsite backups over the wire).
> 
> I use rsnapshot to create backups with history so I can recover deleted/modified files back several months, really important stuff is uploaded to free cloud storage in addition to my local backup.
> 
> I have used RAID in the past, and never had it save me once (have had good luck with drives)... while my backups have saved me many times when things were deleted or changed (something RAID wouldn't have helped with anyway).

I would never consider building anything other than the most trivial and non-critical system without raid. If raid has never saved your bacom then you have been exceedingly lucky - it's saved me many times. Being able to restore from backups is one thing, but can't compete with a system that fails to die on disk failure, and can be recovered online (if you manage to swap drives without killing the system) just by partitioning a replacement drive and adding partitions into the array to be hot-rebuilt.


I would out all the system onto raid1*, but not raid the recordings. If I had a bit more cash to spare, I would raid1 drives (or rather, partitions on them) together in pairs and use the raided volumes for storage - contrary to what many say (myself included until fairly recently), losing a recording drive is "more than a bit annoying".

* Currently I have my system on raid1 volumes pairing an SSD with spinning disk. The spinning disk is configured as "write mostly" (check the --write-mostly flag when creating an array) so that the SSD is used for nearly all reads. If funds run to another SSD then I;d replace teh spinning disk with that - but having lost the system (and had to restore from backups) due to SSD failure then I;d not run just a single drive again.


Andre MythTV <mythtv-list at dinkum.org.uk> wrote:

> On an 8TB drive I get an extra 100GB with Largefile4 and I can’t remember how much -m 0 gained me but it was several movies worth.

IIRC it's 5% by default (without "-m 0, 5% is reserved for root user), which on an 8TB drive is "well worth having" !

> I then run snapraid on the video’s drives ...

Ah, I'll take a look at that.