Hi Jim,

My understanding is that the DLNC can consume quite a bit of memory
too, and the ARC limitations (and memory culler) don't clean the DNLC
yet. So if you're working with a lot of smaller files, you can still
go way over your ARC limit. Anyone, please correct me if I've got that
wrong.

-J

On 3/15/07, Jim Mauro <[EMAIL PROTECTED]> wrote:

FYI - After a few more runs, ARC size hit 10GB, which is now 10X c_max:


 > arc::print -tad
{
. . .
    ffffffffc02e29e8 uint64_t size = 0t10527883264
    ffffffffc02e29f0 uint64_t p = 0t16381819904
    ffffffffc02e29f8 uint64_t c = 0t1070318720
    ffffffffc02e2a00 uint64_t c_min = 0t1070318720
    ffffffffc02e2a08 uint64_t c_max = 0t1070318720
. . .

Perhaps c_max does not do what I think it does?

Thanks,
/jim


Jim Mauro wrote:
> Running an mmap-intensive workload on ZFS on a X4500, Solaris 10 11/06
> (update 3). All file IO is mmap(file), read memory segment, unmap, close.
>
> Tweaked the arc size down via mdb to 1GB. I used that value because
> c_min was also 1GB, and I was not sure if c_max could be larger than
> c_min....Anyway, I set c_max to 1GB.
>
> After a workload run....:
> > arc::print -tad
> {
> . . .
>   ffffffffc02e29e8 uint64_t size = 0t3099832832
>   ffffffffc02e29f0 uint64_t p = 0t16540761088
>   ffffffffc02e29f8 uint64_t c = 0t1070318720
>   ffffffffc02e2a00 uint64_t c_min = 0t1070318720
>   ffffffffc02e2a08 uint64_t c_max = 0t1070318720
> . . .
>
> "size" is at 3GB, with c_max at 1GB.
>
> What gives? I'm looking at the code now, but was under the impression
> c_max would limit ARC growth. Granted, it's not a factor of 10, and
> it's certainly much better than the out-of-the-box growth to 24GB
> (this is a 32GB x4500), so clearly ARC growth is being limited, but it
> still grew to 3X c_max.
>
> Thanks,
> /jim
> _______________________________________________
> zfs-discuss mailing list
> [email protected]
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
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