John,
The Gresham Storage Director provides both iSCSI and/or FC connectivity
for your backup servers and manages physical tape and other devices off
the back-end. iSCSI works well with this and has many good attributes
including using existing infrastructure for remote connectivity. We
have connected a backup server in Texas to a Gresham box in the UK for
example, and performed a backup all the way through to physical tape in
the UK over a VPN tunnel.
Performance is the issue however. WAN performance is impacted by many
things, not to mention the number of "hops" to get to the final
destination along with whether you are sharing the performance of the
WAN connection with other things, but functionally it works fine.
In a local tape environment, you can use iSCSI over a 1Gb Ethernet
network and we generally see about a 50-80MB/Sec data rate (megabyte not
bit) with the Gresham box in this environment. You might say that this
doesn't sound very fast but in reality a given backup server running
from internal disks usually can't push data any faster than that anyway.
Therefore put each backup server on it's own private network if you
wish.
I would say that if you don't have a high bandwidth requirement, iSCSI
over 1Gb Ethernet might be a good low cost solution in the configuration
mentioned above.
However, 10Gb iSCSI adapters are now available and should be able to
give you performance equivalent to 4Gb FC but we are seeing differences
in performance on different adapters and will be testing this more
before we make a selection. The other problem with 10Gb iSCSI right now
is that they are still charging as much or more for these adapters and
switches than they are for 4Gb FC so there is no real incentive from a
cost perspective. Hopefully this will change in the future.
Regards,
Tom Wright
tel: 512-407-2609
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Schneider, John
Sent: Thursday, July 10, 2008 2:20 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] iscsi world as it relates to TSM world
Greetings,
There are a couple people at our company that contend that FC is
going away, and in a very short time everything will be iscsi. I am
afraid I am completely ignorant about iscsi as it relates to tape
traffic. My questions are:
1) Can anybody tell me what is going on in the iscsi world around tape?
2) Are there iscsi software/hardware solutions for Windows and AIX (or
TSM platforms) attached tape?
3) Are there tape drives/libraries with native iscsi support, or are
converters necessary?
4) Have any of you converted from a SCSI or FC tape environment to
iscsi? If so, what were the gotchas?
Thanks in advance for the input.
Best Regards,
John D. Schneider
Lead Systems Administrator - Storage
Sisters of Mercy Health Systems
3637 South Geyer Road
St. Louis, MO 63127
Phone: 314-364-3150
Cell: 314-486-2359
Email: John.Schneider AT Mercy DOT net
This e-mail contains information which (a) may be PROPRIETARY IN NATURE
OR OTHERWISE PROTECTED BY LAW FROM DISCLOSURE, and (b) is intended only
for the use of the addressee(s) named above. If you are not the
addressee, or the person responsible for delivering this to the
addressee(s), you are notified that reading, copying or distributing
this e-mail is prohibited. If you have received this e-mail in error,
please contact the sender immediately.
|
