On 4/20/07, Robert Milkowski <[EMAIL PROTECTED]> wrote:
Hello Wee,
Friday, April 20, 2007, 5:20:00 AM, you wrote:
WYT> On 4/20/07, Robert Milkowski <[EMAIL PROTECTED]> wrote:
>> You can limit how much memory zfs can use for its caching.
>>
WYT> Indeed, but that memory will still be locked. How can you tell the
WYT> system to be "flexible" with the caching?
It shouldn't be locked but in reality it can.
It will be "locked" because there is nothing in its view that is
claiming memory. The machine is a file server and does very little
else that demands memory. cachelist will lose to zio_buffer.
I don't know how SAM-FS works (I've never used it) but I'm surprised
that you started paging via using swap - or perhaps you meant
something else.t
If qfs uses standard page cache perhaps increasing segmap would also
help. It's still static however.
How do you increase segmap?
By limit ZFS arc you are not disabling prefetching or any other
features.
First I would be most interested what exactly happened when your
server started to crawl 'coz you can't "swap out" page cache or arc
cache...
It wasn't a case of swapping. In fact, the problem is exactly the
reverse. There was not enough memory demand to kick ARC to scale back
on its memory usage. In our test runs with ZFS serving as copy1 for
SAMFS, we saw ZFS using up 1.5-2GB of RAM even when the system is
idle. The cache is leftover from the previous archiving activities
and is unlikely to be reused. I'd rather the memory be used by SAMFS.
--
Just me,
Wire ...
Blog: <prstat.blogspot.com>
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