In message
<[EMAIL PROTECTED]>,
Michael Martin <[EMAIL PROTECTED]> writes
Found this on IBM's website.
http://publib.boulder.ibm.com/infocenter/systems/index.jsp?topic=/com.ib
m.aix.baseadmn/doc/baseadmndita/page_space_trouble.htm
Paging space troubleshooting
The most common problem regarding paging space is caused by running out
of allocated space.
The total amount of paging space is often determined by trial and error.
One commonly used guideline is to double the RAM size and use that
figure as a paging space target. If paging space runs low, processes can
be lost, and if paging space runs out, the system can panic. The
following signal and error information can help you monitor and resolve
or prevent paging space problems.
I got involved in a little spat over these recommendations. I know I'm
talking about Linux not AIX here, but ...
Early in either the 2.4 or 2.6 series, Linus decided that the memory
management code needed sorting out, so he deleted all the error handling
/ optimisation / "what to do if swap is tight" sort of code. What came
out of this was that the standard Unix swap algorithm NEEDS twice ram of
page space to function efficiently.
So if people tell you that the "twice ram" rule is "just a rule of thumb
you can ignore", well it may or may not be. There certainly WERE very
good reasons for it - whether those reasons are still valid I don't
know, but certainly on any system still using the old "traditional" Unix
algorithms it's still a very good rule you *should* follow - and as a
*minimum*, not a *target*.
Me - disk space is cheap so I always have swap as a minimum of twice my
motherboard's maximum ram. Actually, on my current system (max ram =
768Mb) I've got a 10Gb swap, but I've also got /tmp mounted as a tmpfs
file system which stuffs the whole lot in ram (or swap, as the case may
be :-)
Cheers,
Wol
--
Anthony W. Youngman <[EMAIL PROTECTED]>
'Yings, yow graley yin! Suz ae rikt dheu,' said the blue man, taking the
thimble. 'What *is* he?' said Magrat. 'They're gnomes,' said Nanny. The man
lowered the thimble. 'Pictsies!' Carpe Jugulum, Terry Pratchett 1998
Visit the MaVerick web-site - <http://www.maverick-dbms.org> Open Source Pick
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