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kernel tuning rx8620

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Honored Contributor

kernel tuning rx8620

Hey all,
I have a rx8620 with 16 cpus and 64 GB memory. The server is going to run a Sybase.

Is there a recommendation for optimal kernel tuning 1st for a server of this sice 2nd for a server of this size running Sybase.

BR, Jannik
Bill Hassell
Honored Contributor

Re: kernel tuning rx8620

There is no answer for this question as stated. The current default settings will be fine as long as no users logon to the system and Sybase uses raw disks for data. You need a *LOT* of additional information such as access methods (telnet, ssh, ftp, database ports), the maximum quantity of connections, the maximum number of files and network ports that will be open at the same time, the number of additional applications and middleware that will be part of the Sybase system, expected printer counts, backup programs, and so on. You can look at the individual parameter descriptions at:

Bill Hassell, sysadmin
Steven E. Protter
Exalted Contributor

Re: kernel tuning rx8620


Sybase has kernel tuning requirements for systems. As with most databases, shared memory is used. I recommend using the kernel to set shmmax to 25% of memory, which HP defines as ram plus swap.

dbc_max_pct should be around 10%
dbc_min_pct should be around 5%

vx_ninodes should be set to a reasonable number and not left at the default wich is zero.

nproc and maxuprc and a few other parameters will require adjustment.

Steven E Protter
Owner of ISN Corporation
Honored Contributor

Re: kernel tuning rx8620


I did the following:
kctune -B dbc_min_pct=1
kctune -B dbc_max_pct=1
kctune -B vx_ninode=20000
kctune -B nproc=10000
kctune -B nkthread=20000
kctune -B nproc=10000
kctune -B maxuprc=5000
kctune -B maxssiz_64bit=1073741824
kctune -B maxssiz=134217728
kctune -B maxuprc=9000
kctune -B msgtql=10000
kctune -B msgmap=10002
kctune -B msgseg=32767
kctune -B semmni=4096
kctune -B shmmni=512
kctune -B vps_ceiling=64
kctune -B ksi_alloc_max=80000
kctune -B msgmni=10000
kctune -B ncsize=96384
kctune -B semmns=8192
kctune -B semmnu=9996
kctune -B shmmax=68719476736

I asked HP what there recommendation was, They said the same as Steven. I then startet reading though the document Bill send thats perfekt.