Messages in this thread | | | Date | Fri, 5 Jun 1998 00:34:44 +0100 (BST) | From | Riley Williams <> | Subject | Re: Multiple swap partition uglies (fwd) |
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Hi James.
>>>> Rik - the problem is NOT with swapoff. Swapoff'ing one of the >>>> drives actually solves the problem (ok it takes a while, but this >>>> is no different from the performance I get _all the time_ when >>>> swapping off two drives). The problem is with the 2 swap drive >>>> setup. Sometimes, paging takes forever. When I swapoff one of the >>>> drives, to revert to a 1 swap partition setup, the problem goes >>>> away.
>>> Absolutely clear. You have 1 disk off of which the programs, >>> libraries and other files are paged and is used for swap and >>> another disk which is used for swap and not-often-used data.
>>> This means that the first disk will have to perform double >>> duty, which can be very slow, especially when the swap partition >>> is physically remote from the / and /usr partition.
>> I don't think that's the problem since I can reproduce it here, and on >> my setup, neither of the swap partitions are sharing a drive with the >> executables. Here's the system map for reference:
>> Q> /dev/hda => / /usr /usr/local /root >> Q> /dev/hdb => /usr/doc /tmp (swap) /home >> Q> /dev/hdc => /usr/src (swap) /home/ftp
>> It appears to be a bug that only shows itself when multiple swap >> partitions have the same priority, since it doesn't appear when they >> have different priorities, and this suggests that there's something up >> with the round-robin algorithm referred to in the swapon/swapoff >> manpages...
> Well I've got (from memory, I'm at work atm)...
> /dev/sda /usr swap pri=2 > /dev/sdb / swap pri=1 > /dev/sdc /boot swap pri=1
> Which seems is working fine.
Can you confirm that setup? If so, it narrows the conditions down further - ALL swap partitions must have the SAME priority for the bug to hit...
Best wishes from Riley.
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