This article gives us confidence in the fact that IBM now see deduplication as
an essential part of the storage environment. Maybe your (and my) wishes for
integrated deduplication within the TSM server will soon be answered.
I say soon, I mean a couple of years..
http://money.cnn.com/news/newsfeeds/articles/marketwire/0388142.htm
------
Matthew Large
TSM Consultant
Storage Services
Barclays Wealth Technology
Desk: +44 (0) 207 977 3262
Mobile: +44 (0) 7736 44 8808
Alpha Room, Ground Floor Murray House
1 Royal Mint Court
London EC3N 4HH
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Paul Zarnowski
Sent: 18 April 2008 15:25
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Fw: TSM being abandoned?
A few more points:
- It's true that hardware compression is faster than software compression,
and off-loads the server. Hardware compression often is an extra-cost
item. This can also be true of encryption, if done in hardware. The
question is, where do you want to do your encryption? At the storage
device, on the network, or in the client? Depends on your requirements.
- Deduplication is going to take processing time wherever it's done. Be it
by TSM on the TSM server, or by the VTL either in-band or
out-of-band. Just because it's done out-of-band doesn't mean that you
don't have to worry about performance. You still only have 24 hours in a
day to get everything done that you need to get done.
- TSM is in the best position (IMHO) to do deduplication, because it knows
most about the data. To illustrate this, consider the following: Even
with a VTL, you will still be doing TSM Tape Reclamation. With a VTL, the
input tape will have to be "rehydrated" as it is read, and the output tape
will have to be "re-dehydrated" as (or after) it is written. TSM, on the
other hand, could know that the data on the input tape has already been
dehydrated and therefore doesn't have to be re-dehydrated on the output
tape. It knows what the data is. (n.b., I don't know how TSM will do this
- this is hypothetical - time will tell). There can be other examples of
this also, especially thinking forward. VTLs are more limited in what they
can do. Their advantage is that they can be dropped in to replace a
physical tape library transparently.
- Given that you're going to have to pay for the extra processing one way
or the other (either by the higher cost of a deduping VTL or by bigger
processors on your TSM server), I'd rather invest my money where the most
intelligence can be - in the TSM server. Compare the cost of inexpensive
disk to the cost of the VTL solutions you are considering. Using a
highly-featured disk subsystem for serial-access disk may not be the best
way to spend your money for serial-access-disk. Look at simple SATA arrays.
My last point - there are a few VTLs that have replicating dedup today,
with more "on the cusp". If you need something today, look at what is
available today. If you don't need something until later, re-evaluate the
marketplace later - it's very dynamic right now.
..Paul
--
Paul Zarnowski Ph: 607-255-4757
Manager, Storage Services Fx: 607-255-8521
719 Rhodes Hall, Ithaca, NY 14853-3801 Em: psz1 AT cornell DOT edu
Barclays Wealth is the wealth management division of Barclays Bank PLC. This
email may relate to or be sent from other members of the Barclays Group.
The availability of products and services may be limited by the applicable laws
and regulations in certain jurisdictions. The Barclays Group does not normally
accept or offer business instructions via internet email. Any action that you
might take upon this message might be at your own risk.
This email and any attachments are confidential and intended solely for the
addressee and may also be privileged or exempt from disclosure under applicable
law. If you are not the addressee, or have received this email in error, please
notify the sender immediately, delete it from your system and do not copy,
disclose or otherwise act upon any part of this email or its attachments.
Internet communications are not guaranteed to be secure or virus-free. The
Barclays Group does not accept responsibility for any loss arising from
unauthorised access to, or interference with, any Internet communications by
any third party, or from the transmission of any viruses. Replies to this email
may be monitored by the Barclays Group for operational or business reasons.
Any opinion or other information in this email or its attachments that does not
relate to the business of the Barclays Group is personal to the sender and is
not given or endorsed by the Barclays Group.
Barclays Bank PLC. Registered in England and Wales (registered no. 1026167).
Registered Office: 1 Churchill Place, London, E14 5HP, United Kingdom.
Barclays Bank PLC is authorised and regulated by the Financial Services
Authority.
|
