Hi Ben,
I was remotely involved with this sort of problem about a year ago. Another
hospital in the area had a host machine that was using a FASTt700 and FC
tape over the same HBAs. They had lots of problems both from the disk and
tape point of view and the CE was replacing parts left and right to no
avail. As soon as I heard of their problem I told the CE to have them move
the disk and tape to separate HBAs. But their VAR said no way is that the
problem. So the hospital suffered for another 5 months until they finally
tried it and things worked fine after that.
With the most HBA drivers comes a read.me file that states:
1.2 Limitations
---------------
Inter-operability with tape devices is supported on separate FC HBA and
FC switch zones...
Someone may correct me here, but if memory serves... the tape devices were
put on streaming (selector) channels and disk on block channels. Some tape
operations can use very long sustained continous data streams, thus not
allowing access to the channel by other devices on the same channel. A
problem for timing sensitive disk. Block devices on the hand have smaller
"blocks" of data on the channel and allow other devices more chances to
access the channel.
I have heard of tape and disk coexisting on one HBA and working, but it is
not recommended nor supported by IBM. Your mileage may vary...
-Jeff
SMDC
http://www.smdc.org
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
Ben Bullock
Sent: Tuesday, March 07, 2006 15:15
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: LAN FREE Backup
That brings up a question. I know if the past, we were told not
to mix DISK and TAPE resources on the same FC HBA, but is that
suggestion still valid?
Will it not work at all? Or will it work but extremely poorly
because of the different types of data flows?
Just curious if something has changed in the last few years of
FC architecture that makes this rule-of-thumb no longer apply...
Ben
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Rubie Lim
Sent: Tuesday, March 07, 2006 2:09 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: LAN FREE Backup
Thanks. I have 3 clients to put on LAN FREE backup, but 2 of them cannot
have more than 2 HBA's, what route should I go? And these 2 HBA's is
needed for disk for redundancy.
Rubie
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Nast, Jeff P.
Sent: Tuesday, March 07, 2006 10:24 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] LAN FREE Backup
Yes, you need to zone tape drives to the machine running Storage
Manager.
Multiple tape drives can use the same HBA.
Tape and Disk cannot coincide on the same HBA. You need a separate
adapters for disk and tape. This stems from the days of S360 (and
earlier?) where there were seperate channels for streaming channels
(tape) and block channels (disk). Guess this dates me...
-Jeff "old timer" Nast
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
Rubie Lim
Sent: Tuesday, March 07, 2006 10:01
To: ADSM-L AT VM.MARIST DOT EDU
Subject: LAN FREE Backup
I am trying to implement a LAN FREE backup, and my question on the
Storage Agent/Client, do I need to create a zone from one of my HBA to
the Fiber Channel Tape drives? And if I can share the HBA with disk and
tape?
Any help is greatly appreciated.
Thanks,
Rubie
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