Your best bet is to always wait for the more cogent description of the
solution before proceeding. You can always count on Wanda to clean up
my mess!
In fact, I think I'll steal this as it is a very concise description of
when/why you might consider a VTL. Perhaps the most concise description
written...
Thanks,
Kelly J. Lipp
VP Manufacturing & CTO
STORServer, Inc.
485-B Elkton Drive
Colorado Springs, CO 80907
719-266-8777
lipp AT storserver DOT com
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Prather, Wanda
Sent: Wednesday, December 06, 2006 3:09 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Survey Question for Virtual Tape Users: What
Vendors are you using for Virtual Tape?
I concur with Kelly's evaluation.
Where VTL's really shine:
-On restores of multiple files (like restoring a large directory
of small files),
no tape mounts are required, even if data is not
collocated
-Since you don't need to collocate, migration and on-site
reclamation are much faster.
-Reclamation of offsite tapes is MUCH faster, as the input tape
mounts are eliminated
But most VTL's on the market are made with SATA disk, which are at the
low end of disk performance. Depending on the vendor, model,
configuration, and your client hardware, backup & restores from VTL's of
a SINGLE LARGE FILE file may not be any faster than (fast) tape. And
then there is the question of how fast your SERVER can push data (most
of my customers don't have servers yet that are capable of pushing LTO3
drives at full speed!)
So you need to REALLY figure out where your bottleneck is before you
decide how to fix it.
-If what is causing you to run slowly is MOUNT times, you need a VTL.
-If what is causing you to run too slow is WRITE time, and your write
speed/sec is already up to LTO2 speed (30-35MB/sec), it may be more
cost-effective to drop in LTO3 drives, which are more than twice as
fast. (75-80MB/sec for IBM LTO3).
-if what is causing you to run too slow is WRITE time, and your write
speed/sec is less than 30-35MB/sec, it isn't the LTO tape that's causing
your problem - your bottleneck is somewhere else! (like your server DB,
your network, your diskpool, the client etc.).
That being said, implementing a VTL is very easy and has many benefits.
However, if you decide to go with a VTL, MAKE SURE you get a commitment
from the vendor of how many MB/sec SUSTAINED throughput they support, so
you have an idea just how fast you can push AND /pull 1 TB of data IN A
SINGLE LARGE FILE. There are a lot of VTL's on the market, and they all
have different throughput ratings.
Wanda Prather
"I/O, I/O, It's all about I/O" -(me)
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Kelly Lipp
Sent: Wednesday, December 06, 2006 4:36 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Survey Question for Virtual Tape Users: What Vendors are
you using for Virtual Tape?
Based on your config I'm guessing you're having trouble completing the
backup stg operations due to the fact that you get a single large
process running to a single tape drive (or tape to tape) and that's
taking too long.
I would suggest using the copystg parameter on the primary tape pool and
have that large database go directly to the primary and copy pool tapes
simultaneously. That will eliminate the need to do the backup stg
tapepool copypool operation during daily processing. I would also
backup stg diskpool copypool before I migrate. Again, the goal, I
assume, is to get the backup stg operations completed as early as
possible.
So in summary:
1. Large stuff goes directly to tapepool with copystgpool set to
copypool. You have plenty of tape drives so there should not be any
conflict during the backup.
2. backup stg diskpool copypool maxproc=10 (or whatever) first thing or
maybe even start this during the backup window (careful with that as
that can slow the performance of client backups and the backup stg
operation).
3. Simultaneous with that, backup stg tapepool copypool (just in case
something when afoul).
4. backup db
5. prepare
6. Then do the migrations and other housekeeping chores.
With the number of tape drives you have, I'm thinking with this
rearrangement you should be able to get the work done. I don't think a
VTL would help you anyway! Sorry about that you hardware sellers!
Thanks,
Kelly J. Lipp
VP Manufacturing & CTO
STORServer, Inc.
485-B Elkton Drive
Colorado Springs, CO 80907
719-266-8777
lipp AT storserver DOT com
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Nancy L Backhaus
Sent: Wednesday, December 06, 2006 1:20 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Survey Question for Virtual Tape Users: What Vendors
are you using for Virtual Tape?
Background:
Tivoli Storage Manager Extended Edition 5.3.2.2 Op System AIX 5.3 ML 3
Nightly Backup 2 -2 1/2 TB Library - ADIC I2000 Scalar
18 LTO Tape Drives
LTO 2 Tapes
600 slots
Clients - 135 (Wintel)
AIX -26 (Sybase, SQL, and DB2)
We are looking into Virtual Tape Technology for our environment. 1
1/2s
TB data first backs up to disk then to onsite tape then we make a backup
of our onsite tape to a copy stgpool and store those tapes offsite for
disaster recovery. The other 1 TB of data is a DB2 database that we
back up directly to onsite tape and of course make a copy of the onsite
tape to offsite tape for disaster recovery. We can't get our backups
done and out the door to meet our RTO objective. We are looking to
add
a VTL and reduce our tape drive and slot capacity in a new library to
offset some of the cost for a virtual tape library. We would like to
also take advantage of collocation and setup library sharing too.
I would like to know what vendors you are using for virtual tape?
Pros/Cons(Any regrets, Success Stories).
Thank You.
Nancy Backhaus
Enterprise Systems
(716)887-7979
HealthNow, NY
716-887-7979
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