ADSM-L

Re: Anyone do IDE for spool disks?

2003-03-24 15:17:54
Subject: Re: Anyone do IDE for spool disks?
From: Alexander Lazarevich <alazarev AT ITG.UIUC DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 24 Mar 2003 14:17:13 -0600
Thanks dude! I can't wait for the library, I'm drooling! We are currently
using magstar tapes, and I'm really looking forward to the upgrade. Any
idea on where I can get specs for the 3575 magstar tapes, specifically
seek times? I've never actually spec them out, and I'm curious to know
what they are.

Crap, I forgot about the database having tons of random read/writes. I was
planning on putting the OS and the database on the same IDE RAID 1 mirror.
But I think you are right, that's not such a good idea for the database.

Maybe I'll do this:

- Redhat linux 7.3 system and TSM server install on an IDE mirror via a
  promise TX100 controller
- database on a single SCSI drive, backedup to tape
- spool be IDE RAID 0 on it's own channel via a promise TX2000 controller,
  or software RAID, whatever performs better

Does that sound lagit to you?

Alex
---                                                               ---
   Alex Lazarevich | Systems Administrator | Imaging Technology Group
            Beckman Institute - University of Illinois
       alazarev AT itg.uiuc DOT edu | (217)244-1565 | www.itg.uiuc.edu
---                                                               ---


On Mon, 24 Mar 2003, Dan Foster wrote:

> Hot Diggety! Alexander Lazarevich was rumored to have written:
> >
> > We are getting TSM 5.1 server, and want to run it on a linux box. Our
> > library will probably be the OVerland Storage Neo 4100 with LTO-2 drives.
>
> Lucky weenie! (LTO-2)
>
> We put the LTO-1 library in production yesterday, and compared to the
> 3575... ***WOW***!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
>
> Not only that... we backed up 136 nodes on 2 or 3 LTO tapes compared to
> 100-ish Magstar tapes.
>
> That thing eats combat boots - an entire division's worth - for breakfast,
> and is still hungry at lunchtime!
>
> I think you'll like the LTO-2 *even* better. :)
>
> > We also want to have some spool space, and SCSI is the first thought. But
> > since IDE is getting cheaper and faster, I'm wondering if anyone has tried
> > out IDE as spool disks between the PC and the tape library. We could go
> > with either software or hardware RAID 0 (striping), which would further
> > increase the IDE performance. We also plan on upgrading our network to
> > Gigabit in a few months, so we don't want the spool disks to be the
> > bottleneck.
>
> Well, for our LTO-1 library, the network was the major bottleneck, rather
> than CPU, memory, disk, or tape. The FE was *SO* pegged it was
> unbelievable... 10,000 to 15,000 packets per second and the rest of system
> was *very* bored! If we had gig-e, we'd have stuffed a lot more data in
> there, much more quickly.
>
> > But since SCSI still outperforms IDE in relation to concurrent
> > operations, which the spool disks will most likely be doing (I.E.
> > writting from network, reading to tape), then maybe IDE is a bad idea.
>
> If you're doing this for a diskpool, I honestly wouldn't sweat it. I think
> IDE sounds fine for this purpose. It's just when you have a database that
> it would be more sensitive to this... but since not the case...
>
> A diskpool is mostly one-write-only traffic... not like it's a database
> type of disk with lots of little random read/writes.
>
> We're also looking at a cheap $12K 1 TB drawer with IDE disks (and a SCSI
> attachment to the host server); it's looking like a winner for diskpool at
> this point.
>
> -Dan
>

<Prev in Thread] Current Thread [Next in Thread>