I have a Sepaton VTL and it has helped us tremendously to meet our
requirements.  Although the VTL did help reduce our backup window by over
70% and we have sustained backup speeds of 150MB/s and I have seen them
has high has 300MB/s.  You are going to need to reconfigure the way your
clients backup for example you may need to reconfigure your db2 client for
better disk read performance and send data using multiple TSM sessions
most of the time the client is the bottle neck.  Then you should start
looking at your TSM server, we had to implement aggregate multiple gig
network cards just to handle the client throughput.  You may also need to
implement multiple san cards to your disk storage or vtl to get the
required throughput.

In my experience with vtl's they do write much faster than regular disk
pools and tape drives.  We use TS1120 drives and I was not able to get
better throughput to my tape drives than I am getting to the VTL. And the
tape drives are supposed to be faster.


On Wed, December 6, 2006 4:41 pm, Kelly Lipp wrote:
> 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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