Thanks to the people who responded.
robert_at_gnsconsulting.com.au replied,
I would guess you could go as high as you want. In other words I don't
think you would want to set it higher than 512M on this machine you are
talking about. Therefore you won't have to worry about how high you can
set it. I have seen it at 4G on an 8400.
Willig.Reimund_at_gdr.dr responded with,
The max size of a System V Shared memory segment is 2GB.
Benoit.Sylvain_at_digital.com added,
Using dxkerneltuner, you set the maximum value to 2147483647 ( 2Gb )
Tony.J.McGovern_at_aib.ie and Davis_at_Tessco.Com provided the means to check
the max values:
Use the sysconfig -Q <subsys> to get min and max values.
sysconfig -Q ipc
...
shm-max - Type=INT op=CQ min_val=0 max_val=2147483647
...
shm-max is : 2gb - 1byte
Caprica7_at_aol.com provided information as to what the value is used for:
The "shm-max" value is the maximum size of a single System V shared
memory region. This will be expressed in either bytes or a number of
pages (8K, unless you've changed this) in your kernel, and it'll show
up in /etc/sysconfigtab if you've manually tweaked this value.
So what does this mean? Some applications utilize System V-style memory
management. We have one at our site: An enterprise app built around an
Informix engine that uses System V memory management. So we have to
tweak these values for performance. If you don't have an app that uses
System V memory management, then you can forget about this, and its
associated values.
To summarize,
As this system only has 512 Mb of RAM, I will be configuring shm-max to
256 Mb. This will give us a starting point. Some of my 3.2 systems
have this value set to 8 Mb.
Thanks to all of the contributors.
Simon.Millard_at_barclays.co.uk
Address Telephone
CAS - GES/Open Systems Support External: (01202) 601155 ext 2417
Barclays Technology Services Internal: C/W 7-4160-2417
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Poole, Dorset
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Received on Mon Feb 15 1999 - 13:09:32 NZDT