Hyperthreading (i.e. on linux) slows down perform. ? affect on Availa.Index?

HCL Domino Domino Forum
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Dear all,

HP ML570 2x Xeon 2,8

Suse Enterprise Server 8 with Domino 6.5.1

So my 2 clustered new servers for 600 user are runnig excellent. Hyperthreading is activated so linux shows and scales (??) 4 processors…

Now, compared with my “older” system and same workload (mostly avail.index of 100), my new stronger systems shows a lot of jumps from 0 - 100 availa.index… but performance is quite good and no failover…

After 2 weeks of testing and monitoring i feel HT is responsible for this behaviour and it slows down domino performance?

Tomorrow i will start a new test with deactivated HT… using only two strong physical cpu’s :wink:

What do you thinking about HT and Domino, specially on linux ??

Any input is highly welcome!

best regards,

Jimmy

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Subject: Hyperthreading (i.e. on linux) slows down perform. ? affect on Availa.Index ?

I found this document yesterday that may help.

http://www-10.lotus.com/ldd/nd6forum.nsf/55c38d716d632d9b8525689b005ba1c0/b7375b29a6ac7a7cc1256de00034a225?OpenDocument&Highlight=0,availability,n%3Ftes.ini

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Subject: Hyperthreading (i.e. on linux) slows down perform. ? affect on Availa.Index ?

Maybe - I’m seeing the same thing on older P4-based servers running at 1.1GHz, both running dual processors. No HT at all. This is on Windows, mind you, but the availability.index seems to be much more sensitive since switching to D6 and above. This may be platform-dependent, though.

There is a KB article that covers this, and shows how to make availability.index a more realistic indicator of system performance.