5 May
2010
5 May
'10
10:14 a.m.
Hi,
On Tuesday 04 May 2010 16:12:39 plutek wrote:
i'm looking at my pile of external audio drives
and backup drives, and
wondering about better solutions.
a friend has recently mentioned multiple-drive bays, which allow you to
swap raw drives in/out at will, eliminating all the individual enclosures.
we also had a discussion about bays which implement hardware RAID for
realtime mirroring.
i'm wondering if any of you have experience with these sorts of devices in
the context of linux multitrack audio work. specific concerns might be
things like:
1. reduction of total throughput in a combined-disk device relative to
separate drive enclosures connected to their own USB ports
I think the bottleneck here is usb, not disks...
2. reduction of total throughput caused by the RAID
mirroring process, even
when it is done by dedicated hardware
3. linux compatibility
4. expense
any experience and/or recommendations about doing this sort of thing would
be most welcome! thanks in advance.
Here is my advice:
Don't do hardware-raid! Neither the real nor the "soft" hardware raid help
you
that much. What do you do when the controller fails?
With a hardware-raid you have to have a second of the same kind in stock to
get back the data on your disks. Don't even think about not having a spare
controller and buying one when yours fails.
Murphies law says the controller will fail at exactly the time you have a
_very_ important project going on and the controller to use is not sold
anymore.
With a software-raid you just plug the disks in another machine/controller and
return to working on your project.
The "reduced" throughput of a software-raid is worth the ease of use. And its
not that "reduced" at all.
Oh, and use only raid1 or combinations of 0 and 1. For all the others see
http://baarf.com.
And if you want more freedom for your disks and partitions, use lvm. Just this
month I had a disk in an array of 5 that announced its failing in smart.
Marked the raid1-copy of the systempartition on that disk as faulty (hot-spare
kicked in), did lvmove to move all the logical volume off that disk and carried
the disk to my dealer for an rma. Two weeks later I shoved in the
replacement... Server uptime: not interrupted. Admins sanity: not influenced.
Of course that only works if you have *some* free space on the physical
volumes.
Arnold