ADSM-L

Re: [ADSM-L] TSM SAN Storage Agent on HP Blade - sharing disk and tape?

2009-09-30 08:23:20
Subject: Re: [ADSM-L] TSM SAN Storage Agent on HP Blade - sharing disk and tape?
From: Steven Harris <steve AT STEVENHARRIS DOT INFO>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Wed, 30 Sep 2009 22:22:20 +1000
David,

I used to think that sharing disk and tape on the same HBA was only FUD spread to make you buy the bigger server. I used mixed disk and tape on windows servers from HP, Dell and IBM for years without a hitch. However, within the last 12 months I had a customer with 4 IBM Xseries boxes in a Windows 2003 cluster, running three instances of Exchange. Disk was IBM DS4000. The exchange stores were corrupted more than once, and there was much wailing and gnashing of teeth.
It was put down to shared HBAs

Regards

Steve

Steven Harris
TSM Admin, between jobs, Sydney Australia

David McClelland wrote:
Hi Steven,

Thanks for your thoughts - disk resilience between the two ports on the
blade is an unmoveable for the customer, so sharing disk and tape traffic
over the same ports is really the only option, if the SAN Storage Agent is
to be used. After opening a query with IBM about this config, their response
was: "Recommended=no; supported=yes". I've spoken with another colleague in
IBM who's run with a similar config, albeit using IBM blades rather than HP.

Does anyone have any practical recent experiences of running successfully
(or otherwise) sharing disk and tape? My understanding from wider reading is
that sharing disk/tape through the same HBA port is less of an issue with
recent hardware and firmware etc. Finding published statements is a little
more difficult, I've found.

FYI, the tape drive tech the customer is now using is IBM TS1130, and
they're looking to achieve recovery of around 1TB within a target of around
4 hours (RMAN/TDPO data) from their Linux x86 hosts (actually, a three way
Oracle RAC cluster).

Many thanks,

/David Mc
London, UK



-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Steven Langdale
Sent: 30 September 2009 09:47
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] TSM SAN Storage Agent on HP Blade - sharing disk and
tape?

David

Not 100% sure on the HP Bladecenters, but I do have experience with the IBM ones - probably all of a muchness.

The IBM ones can either use passthru modules (which present every port of the dual port card on each blade) or switches. From what you are saying, I'd have thought you have switches.

However this does not alter your issue.

You have 2 options:

1.  Stay separate and have no resilience for Disk or tape
2. Keep resilience and share the ports for both disk and tape. (as you have said)

FWIW, I'd have a go at option 2 as possibly the safest option.

how much data are you backing up and to what target drives?

Steven

Steven Langdale
Global Information Services
EAME SAN/Storage Planning and Implementation
( Phone : +44 (0)1733 584175
( Mob: +44 (0)7876 216782
ü Conference: +44 (0)208 609 7400 Code: 331817
+ Email: steven.langdale AT cat DOT com



David McClelland <tsm AT NETWORKC.CO DOT UK> Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
29/09/2009 14:01
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"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>


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Subject
[ADSM-L] TSM SAN Storage Agent on HP Blade - sharing disk and tape?




Caterpillar: Confidential Green Retain Until: 29/10/2009


Hi Guys,

A customer has just come up with a request to run the TSM SAN Storage Agent
on a dedicated blade within an HP BladeSystem c7000 blade chassis.

Is anyone running with a SAN Storage Agent (it'll be Linux x86 with TSM 5.5)
in this kind of config?



I'm concerned about shared HBA/fibre access that I believe these blade
centres run with - the recommendation has always been to segregate disk and
tape traffic, but with virtualised HBAs I'm a little unsure of where I
stand. From what I have read of these systems, each blade has two HBA ports
internally, but the HP Blade Chassis presents these as 8 (4 per fabric)
outward facing 4Gbps ports (via some kind of passthrough mechanism). The
storage team say that they are zoning each of the ports within the blade to
disk (they run dual-fabric). This suggests to me that the only way we can
get the SAN Storage Agent to work here would be to zone in the tape drives
to these ports too, but that would result in sharing disk and tape which the
recommendation is not to do.

To clarify, the Linux servers each have their own blade, there's no OS
virtualisation going on for them, so this IBM.com article doesn't seem to
apply, or isn't particularly clear for me:
http://www-01.ibm.com/support/docview.wss?rs=0
<http://www-01.ibm.com/support/docview.wss?rs=0&uid=swg21239546>
&uid=swg21239546


Can anyone offer any guidance or experiences...?

Thanks,

/David Mc
London, UK

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