On 23 okt 2009, at 00:13, Dury, John C. wrote:
We are currently running TSM server v5530 under AIX. The AIX server
has a mixture of different speed (266mhz and 133mhz, both 64bit) PCI-
X slots. With 4 4g HBAs. Our system is connected to a Clariion
CX3-80 where the TSM DB and Recovery Log and Disk Storage pools
live. The disk parts of TSM have 2 4G HBAs and powerpath installed
and configured for load balancing across both. We have 2 STK SL500
libraries, both with 4 LTO4 drives. One is local and the other is
connected via a 2 2G fiber paths to our remote site. The remote
SL500 is defined as a copy storage pool. All of the local tape
traffic is on one HBA and the remote is on another. Disk and tape do
not have any traffic on the same HBAs ever. I used a script I
found in past emails and the best performance we can get on the
local SL500 is around 30MBs. The best performance we can get on the
remote library is about 10MBs. We recently redid the AIX box and
rezoned so the disks would be using the fastest PCI-X slots and the
tape would be using the slower ones to try and improve disk
performance. This did help some as expiration was running for about
8 hours and now it runs in about 4. Our TSM DB is 76800 MB and is
75% full right now. I've looked through the latest TSM performance
and tuning manual and tweaked everything as per recommendations for
our setup.
We are considering migrating our AIX server to an Intel based Linux
box that has a mixture of 8x and 4x PCI Express slots in hopes of
maximizing performance on both disk and tape and also saving money
as AIX boxes are considerably more expensive.
So here are my questions:
1. How hard is it to move from an AIX TSM server box to a
Linux TSM server? I'm hoping it's as easy as building the new box
(tape drive,stg pool etc) and then restoring the DB and tweaking the
new config. I know there is more to it than that but without
researching it yet, that seems like a logical high level overview.
basically, you either start from scratch or export/import, there is no
backup/restore that works, or even if it would work, is supported.
2. Will there be much of a performance difference between and
AIX based TSM server and a Linux based TSM server?
IMNSHO, IBM pSeries hardware is the best there is for large I/O
workloads. I've seen AIX do things that Linux wouldn't survive.
3. Going from mixed speeds slots of PCi-X to PCI Express 8x
and 4x slots should be a significant improvement correct?
The good and the bad news is that both architectures have their week
points. With PCI-X you had to know that your HBA could potentially
saturate the entire PCI bus, and that the bus speed of a PCI-X bus
would drop to 100 MHz if more than one PCI card is present. With PCI-
Express, each adapter has a dedicated connection to the controller,
but the bandwidth from the controller to the system might be less than
the aggregated bandwidth of all PCI-E slots that it controls. A proper
layout of your adapters will give you the best performance, and in
either case you might have some empty slots, though that is more
likely with PCI-X than with PCI-E.
I know there are a lot of factors here but we are concerned we
aren't getting the best performance for our existing hardware. 30MBs
(not Mbps) for a LTO4 drives seems pretty slow and with 4 4x PCI-E
and 4 8x PCI-E slots, I can balance out the I/O across cards and
slots much better than I can now.
Comments and criticisms? Linux vs AIX?
Thanks for any insight!
--
Met vriendelijke groeten/Kind regards,
Remco Post
r.post AT plcs DOT nl
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