[SGVLUG] scary RAID 5 going going .. soon 2 be gone?

[Claude Felizardo]

On Mon, Jan 12, 2009 at 9:26 PM, matti <mathew_2000 at yahoo.com> wrote:
>
> Hi,
>
> well not quite, however you want to read this
> article
>
> summary:
> As Hard Drives get larger, and unrecoverable read error (URE) rate
> remains about the same, the chances of being able to recover from a
> disk drive failure on a RAID 5 system goes down (i.e failure rate increases )...
> so much so that you may expect to not be able to reliably recover.
>
> scary math, especially considering what a PITA it is to backup large amounts of data.
>
> Why RAID 5 stops working in 2009
> http://blogs.zdnet.com/storage/?p=162
>
> best
> matti

Yeah, this article and a bunch of articles warning about RAID came out
in 2007 and it's been on my mind since I use both RAID-1 and 5
partitions in my fileserver at home.  Most of my important stuff is
backed up on other computers but there's quite a bit of stuff I
wouldn't want to lose but is it's kinda difficult to backup
automatically such as my favorite TiVo recordings.  I've had various
failures over the years that either took the system down completely or
just the big RAID partitions.  It's a pain to rebuild since it
requires commands you type in only once in a while and it takes so
darn long to run that I've been contemplating moving my data to an
external network device.

Right now I've got three 500 GB SATA drives partitioned as follows:
three RAID-1 w/ hot spare on different disks for /boot, / and /alt
(same size as the 2nd for previous/next OS install) and one big giant
RAID-5 with LVM for /home, /export (my shared files and /.private for
the rsnapshot backups)  Yeah, I really would like something like ZFS
for the flexibility of resizing partitions and snapshotting.

At this point, would I be better off adding a 4th drive as a hot spare
or rebuild for RAID-6 for protection against data loss in case a 2nd
drive dies while rebuilding?  Actually are there tools to convert
RAID-5 into RAID-6?

Has anyone looked into any of those online backup services?  Looks
like there's Mozy or Carbonite?  I assume they don't support Linux
partitions so can you configure these things to backup your network
shares as well?  Assuming you want to spend the days to back things up
initially...

What about those 1-touch backup drives from the various drive
manufacturers?  Does anything support Linux w/ 1-touch so it will get
done?  Right now I have to plug in an external drive, mount the
various partitions and copy stuff manually, disconnect, etc.  During
the summer or at least during heat waves I have to use an external fan
blowing on both the fileserver and external  drive box because these
things get hot when you run them for hours at a time.

claude