[ale] IDE Raid / Hotswap

[Robert L. Harris]

Sorry about your loss, sorry to hear it.

I missed the original post somewhere.

I'm running a Legato Networker backup system at work.  We have a
Dual-Proc linux box that's the "server" which has multiple interfaces.
One to the networks it backs up (2 actually, one is a private controll
connection for us to SSH in) and one to a private Gigabit Lan.  The Gig
connection has a couple linux boxes on it which export filesystems to
the server.

Each nfs server has two 8port 3ware IDE disk controllers.  Some machines
have 100Gig drives, some have 160Gig.  I'm using linux software RAID5 as
the 3ware implementation was rather slow at the time the machines were
built.  The machines are Dual 1.2-1.6Ghz boxes with 512Megs of ram.

When I got the machines they had 1 huge raid array of almost 2TB.  Great
for space but a real nightmare for management.  There'd be directories
with 50000 files which were a pain to clean up.  Tack on that any 2 of
16 drives failing would wipe out the whole array.  I converted them to
four 4disk RAID5 arrays of about 1/2 a TB each.  Much faster, allows for
more streams to the real disk which seems to be multiple drives to the
server.  In addition the odds of loosing any one of the array's to a
failure of 2 disks is much lower.

All in all it works great.  If you get Western Digital drives and they
seem to fail semi-randomly let me know, there's a patch...



Thus spake Danny Cox (danscox at mindspring.com):

> Mike,
> 
> On Fri, 2003-04-25 at 00:08, Mike Lockhart wrote:
> > I need to setup a hotswap raid array for backups at work, and I'm
> > thinking of using IDE Raid instead of SCSI due to cost issues.  Does
> > anyone know of a good controller card that supports IDE and hotswaping? 
> > Additionally, what are some good applications to use for backups?
> > (*linux of course*)
> > 
> > My initial thoughts are somthing like using three 8drive IDE raid cards,
> > a dual proc box, and 2 gigs of ram.  I think if I use a board that has 3
> > 66MHz pci slots that it should do ok. (Based of google research and this
> > link:http://www.tomshardware.com/newsletter/vol3/16/70tb.html).
> 
> 	Sorry I've taken so long.  My mom-in-law passed away last Sunday, so
> the last week has seen very little of me actually reading ALE.
> 
> 	Nevertheless, I have IDE hot-swap working with Promise and Highpoint
> chipsets.  In fact, I think it's pretty generic at this point.  The main
> thing to keep in mind is to have ground established when inserting the
> drive.  Using rails to do this is usually sufficient.
> 
> 	If you want the patch for 2.4.20, I'll be happy to send it to you. 
> However, it's only one half of the equasion.  The boxes I used had an
> ACPI function that would "notice" when a drive was removed or inserted. 
> We have a kernel thread polling that memory byte, which upon a change,
> would call my routines to handle it.  If you don't need that aspect, and
> just want to do things manually, then my patch will work as is.  It
> creates a new directory: /proc/sys/dev/hot-swap, with files add, remove,
> fake_add, fake_remove, hdd_status, and inject_error.  The first two, add
> and remove are the main guys.  When a drive is added, say hda, you
> simply "echo 0 >/proc/sys/dev/hot-swap/add", and the drive is registered
> with the IDE subsystem.  "echo N >/proc/sys/dev/hot-swap/remove" does
> the the opposite.
> 
> 	Drop me a line if you're interested, of if I'm not explaining things
> properly.
> 
> -- 
> kernel, n.: A part of an operating system that preserves the
> medieval traditions of sorcery and black art.
> 
> Danny
> 
> _______________________________________________
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> Ale at ale.org
> http://www.ale.org/mailman/listinfo/ale

:wq!
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Robert L. Harris                     | PGP Key ID: E344DA3B
                                         @ x-hkp://pgp.mit.edu 
DISCLAIMER:
      These are MY OPINIONS ALONE.  I speak for no-one else.

Diagnosis: witzelsucht  	

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