On Thu, 13 Dec 2007, Richard L. Hamilton wrote:
> Sometimes a large system, despite precautions (or in the absence of them),
> runs out of resources (VM, mainly) to the degree that no useful progress
> is being made: that is, one can't even log in and kill the hogging processes.
>
> (At least on SPARC) the usual workaround would be to break to the boot PROM
> and sync; however, this invariably causes a crash dump to be taken. In the
Workaround:
If you have "obpdebug" defined, you can do:
dumpvp 0 x!; sync
at the ok prompt to force skipping the dump.
You could also force it to "don't do it" via /etc/system:
set dump_timeout=0
There are probably a few more undocumented variables to achieve similar.
It's really a question of preference. A "sync --nodump" would only benefit
SPARC; one could argue that SPARC-only features are so last millenium. And
one could ask "why don't you just 'boot' instead of 'sync' then".
FrankH.
> common case where dump partition = swap partition, the dump might
> well not be complete anyway, since swap was already full. And one may
> well know by experience what the likely culprits are.
>
> And on a large system, the crash dump can take longer to complete than
> the subsequent reboot!
>
> So it would be really nice to have an option to force a sync and reboot
> _without_ taking a crash dump. The ability to pass the option would require
> boot PROM support (or else some obscure use of an existing command to
> set something the kernel could readily detect); but the ability to optionally
> _not_ take the crash dump even if it otherwise could and would, would
> require kernel support.
>
> Granted, the situation shouldn't come up all that often. But it has been
> known to do so (and one of the culprits tends to be a 3rd-party system
> monitoring application that I won't name; ironic, IMO, that something
> intended to warn of problems instead causes them); and when it does,
> reducing the down-time by the 5-10 minutes that a really long crash
> dump can take, would IMO be quite helpful.
>
> Am I nuts, or is that a generic enough issue that someone else might
> agree that it's interesting?
>
>
> This message posted from opensolaris.org
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