Amanda-Users

holdingdisk-setup for Ultrium/LTO-2

2009-07-29 17:10:00
Subject: holdingdisk-setup for Ultrium/LTO-2
From: "Stefan G. Weichinger" <sgw AT amanda DOT org>
To: "Amanda user's group" <amanda-users AT amanda DOT org>
Date: Wed, 29 Jul 2009 23:03:02 +0200
Greets, amanda-users,

as I recently got myself an Ultrium 2 drive (at last ...) I wonder how
to optimize performance ...

Right now I only have the amanda holdingdisk on one physical SATA-drive
which seems to work out OK as long as there is no other I/O on that disk ...

The LTO is attached to a good old Adaptec 29160 controller (the only
scsi-device), the server is built around some Intel Prescott CPU (yeah,
kinda old ...) and runs gentoo linux (32 bit).

Right now there are 2 SATA-drives in there, both Seagate, one
ST3500320AS, one ST31000533CS.

The holdingdisk is an LVM2-LV formatted with xfs, the underlying
physical volume is a partition of the ST31000533CS.

I see speeds up to 22MB/s with amanda, but also consider the sound of
the tape-drive accelerating and decelerating could or should be avoided
... afaik it doesn't shoeshine but it doesn't always stream at constant
speed when other apps access the drives.

-->

What I would like to brainstorm:

I think about setting up a software-based RAID0 for the holdingdisk. I
have another ST31000533CS to substitute the smaller ST3500320AS, this
would give me the opportunity to do some shuffling and get a
holdingdisk-raid0 with 100GB or 200GB of size.

I assume the filesystem used for the holdingdisk won't matter as much as
the speed gained by doing the RAID0, so I would maybe just stay with XFS
for simplicity (good with big files ... no headaches ...)

Yes, I know, RAID0 means no redundancy but I would take the risk here ...

Additional q: Does anyone of you use some specific stinit.def for

Host: scsi0 Channel: 00 Id: 03 Lun: 00
  Vendor: HP       Model: Ultrium 2-SCSI   Rev: S63D
  Type:   Sequential-Access                ANSI  SCSI revision: 03

?

Thanks for any feedback,
greetings,
Stefan


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