Displaying 7 results from an estimated 7 matches for "zfs_prefetch_disable".
2009 Nov 18
0
open(2), but no I/O to large files creates performance hit
I''m seeing a performance anomaly where opening a large file (but doing
*no* I/O to it) seems to cause (or correlates to) a significant
performance hit on a mirrored ZFS filesystem. Unintuitively, if I
disable zfs_prefetch_disable, I don''t see the performance degradation.
It doesn''t make sense that this would help unless there is some cache/VM
pollution resulting from the open(2).
The basic situation is that there are 8 SAS applications running a
statistical procedure. The 8 applications read the same...
2007 May 29
6
Deterioration with zfs performace and recent zfs bits?
Has anyone else noticed a significant zfs performance deterioration
when running recent opensolaris bits?
My 32-bit / 768 MB Toshiba Tecra S1 notebook was able to do a
full opensolaris release build in ~ 4 hours 45 minutes (gcc shadow
compilation disabled; using an lzjb compressed zpool / zfs on a
single notebook hdd p-ata drive).
After upgrading to 2007-05-25 opensolaris release bits
2010 Apr 05
0
Why does ARC grow above hard limit?
...e on the backed only reads (205 MB/s) and almost no writes (1.1 MB/s) - any ides what is being read?
--- BEFORE TEST
# ~/bin/arc_summary.pl
System Memory:
Physical RAM: 12270 MB
Free Memory : 7108 MB
LotsFree: 191 MB
ZFS Tunables (/etc/system):
set zfs:zfs_prefetch_disable = 1
set zfs:zfs_arc_max = 0x20000000
set zfs:zfs_arc_min = 0x10000000
ARC Size:
Current Size: 136 MB (arcsize)
Target Size (Adaptive): 512 MB (c)
Min Size (Hard Limit): 256 MB (zfs_arc_min)
Max Size (Hard Limit): 512 MB (zfs...
2010 Apr 02
0
ZFS behavior under limited resources
...9 6937 57%
Total 3141176 12270
Physical 3141175 12270
----------
System Memory:
Physical RAM: 12270 MB
Free Memory : 6966 MB
LotsFree: 191 MB
ZFS Tunables (/etc/system):
set zfs:zfs_prefetch_disable = 1
set zfs:zfs_arc_max = 0x20000000
set zfs:zfs_arc_min = 0x10000000
ARC Size:
Current Size: 669 MB (arcsize)
Target Size (Adaptive): 512 MB (c)
Min Size (Hard Limit): 256 MB (zfs_arc_min)
Max Size (Hard Limit): 512 MB (zfs...
2007 May 14
37
Lots of overhead with ZFS - what am I doing wrong?
I was trying to simply test bandwidth that Solaris/ZFS (Nevada b63) can deliver from a drive, and doing this:
dd if=(raw disk) of=/dev/null gives me around 80MB/s, while dd if=(file on ZFS) of=/dev/null gives me only 35MB/s!?. I am getting basically the same result whether it is single zfs drive, mirror or a stripe (I am testing with two Seagate 7200.10 320G drives hanging off the same interface
2006 Nov 09
16
Some performance questions with ZFS/NFS/DNLC at snv_48
...t 20x more is read from disk
than actually being used. When testing single streams, the readahead
helps and data isn''t thrown away.. but when a bazilion nfs requests come
at once, too much is being read by zfs compared to what was actually
requested/being delivered.
I saw some stuff about zfs_prefetch_disable in current ("unreleased")
code, will this help us perhaps? I''ve read about two layers of prefetch,
one per vdev and one per disk.. Since the current working set is about
1.2TB, 1GB memory in the server and "lots of one-shot file requests"
nature, we''d like to d...
2008 Aug 20
9
ARCSTAT Kstat Definitions
Would someone "in the know" be willing to write up (preferably blog) definitive definitions/explanations of all the arcstats provided via kstat? I''m struggling with proper interpretation of certain values, namely "p", "memory_throttle_count", and the mru/mfu+ghost hit vs demand/prefetch hit counters. I think I''ve got it figured out, but