Displaying 20 results from an estimated 2000 matches similar to: "ARC Tail"
2010 Mar 15
1
persistent L2ARC
Greeting ALL
I understand that L2ARC is still under enhancement. Does any one know if ZFS
can be upgrades to include "Persistent L2ARC", ie. L2ARC will not loose its
contents after system reboot ?
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Abdullah Al-Dahlawi
George Washington University
Department. Of Electrical & Computer Engineering
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Check The Fastest 500 Super Computers Worldwide
2010 Apr 02
6
L2ARC & Workingset Size
Hi all
I ran a workload that reads & writes within 10 files each file is 256M, ie,
(10 * 256M = 2.5GB total Dataset Size).
I have set the ARC max size to 1 GB on etc/system file
In the worse case, let us assume that the whole dataset is hot, meaning my
workingset size= 2.5GB
My SSD flash size = 8GB and being used for L2ARC
No slog is used in the pool
My File system record size = 8K ,
2010 Mar 05
17
why L2ARC device is used to store files ?
Greeting All
I have create a pool that consists oh a hard disk and a ssd as a cache
zpool create hdd c11t0d0p3
zpool add hdd cache c8t0d0p0 - cache device
I ran an OLTP bench mark to emulate a DMBS
One I ran the benchmark, the pool started create the database file on the
ssd cache device ???????????
can any one explain why this happening ?
is not L2ARC is used to absorb the evicted data
2010 Mar 01
1
ARC & Maxphys & recordsize
Greeting ALL
Can someone explain to me why I was successfully able issue (through
application) an I/Os of 128K each (monitored by DTrace) while my Maxphys=56K
only ??????
My understanding is that Maxphys is the max I/O size that the storage device
can handle for a single I/O, it has been well documented that if and
application issued an I/O larger than Maxphys, it would be break down to
2010 Mar 02
9
Filebench Performance is weird
Greeting All
I am using Filebench benchmark in an "Interactive mode" to test ZFS
performance with randomread wordload.
My Filebench setting & run results are as follwos
------------------------------------------------------------------------------------------
filebench> set $filesize=5g
filebench> set $dir=/hdd/fs32k
filebench> set $iosize=32k
filebench> set
2009 Dec 28
0
[storage-discuss] high read iops - more memory for arc?
Pre-fletching on the file and device level has been disabled yielding good results so far. We''ve lowered the number of concurrent ios from 35 to 1 causing the service times to go even lower (1 -> 8ms) but inflating actv (.4 -> 2ms).
I''ve followed your recommendation in setting primarycache to metadata. I''ll have to check with our tester in the morning if it made
2009 Dec 24
1
high read iops - more memory for arc?
I''m running into a issue where there seems to be a high number of read iops hitting disks and physical free memory is fluctuating between 200MB -> 450MB out of 16GB total. We have the l2arc configured on a 32GB Intel X25-E ssd and slog on another32GB X25-E ssd.
According to our tester, Oracle writes are extremely slow (high latency).
Below is a snippet of iostat:
r/s w/s
2010 Dec 21
5
relationship between ARC and page cache
One thing I''ve been confused about for a long time is the relationship
between ZFS, the ARC, and the page cache.
We have an application that''s a quasi-database. It reads files by
mmap()ing them. (writes are done via write()). We''re talking 100TB of
data in files that are 100k->50G in size (the files have headers to tell
the app what segment to map, so mapped chunks
2010 Apr 02
2
How set debug file for RxFax application
Hi Guys,
do any body know how to receive debug info on RxFAX application? i am
experiencing a lot of fax failures and can't guess the reason behind.
Thank you very much for any help!
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Abdullah
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2011 Jan 24
0
ZFS/ARC consuming all memory on heavy reads (w/ dedup enabled)
Greetings Gentlemen,
I''m currently testing a new setup for a ZFS based storage system with
dedup enabled. The system is setup on OI 148, which seems quite stable
w/ dedup enabled (compared to the OpenSolaris snv_136 build I used
before).
One issue I ran into, however, is quite baffling:
With iozone set to 32 threads, ZFS''s ARC seems to consume all available
memory, making
2012 Nov 14
3
SSD ZIL/L2ARC partitioning
Hi,
I''ve ordered a new server with:
- 4x600GB Toshiba 10K SAS2 Disks
- 2x100GB OCZ DENEVA 2R SYNC eMLC SATA (no expander so I hope no SAS/
SATA problems). Specs: http://www.oczenterprise.com/ssd-products/deneva-2-r-sata-6g-2.5-emlc.html
I want to use the 2 OCZ SSDs as mirrored intent log devices, but as
the intent log needs quite a small amount of the disks (10GB?), I was
wondering
2012 Oct 22
2
What is L2ARC write pattern?
Hello all,
A few months ago I saw a statement that L2ARC writes are simplistic
in nature, and I got the (mis?)understanding that some sort of ring
buffer may be in use, like for ZIL. Is this true, and the only metric
of write-performance important for L2ARC SSD device is the sequential
write bandwidth (and IOPS)? In particular, there are some SD/MMC/CF
cards for professional photography and
2011 Apr 25
3
arcstat updates
Hi ZFSers,
I''ve been working on merging the Joyent arcstat enhancements with some of my own
and am now to the point where it is time to broaden the requirements gathering. The result
is to be merged into the illumos tree.
arcstat is a perl script to show the value of ARC kstats as they change over time. This is
similar to the ideas behind mpstat, iostat, vmstat, and friends.
The current
2010 Aug 03
2
When is the L2ARC refreshed if on a separate drive?
I''m running a mirrored pair of 2 TB SATA drives as my data storage drives on my home workstation, a Core i7-based machine with 10 GB of RAM. I recently added a sandforce-based 60 GB SSD (OCZ Vertex 2, NOT the pro version) as an L2ARC to the single mirrored pair. I''m running B134, with ZFS pool version 22, with dedup enabled. If I understand correctly, the dedup table should be in
2009 Dec 03
5
L2ARC in clusters
Hi,
When deploying ZFS in cluster environment it would be nice to be able
to have some SSDs as local drives (not on SAN) and when pool switches
over to the other node zfs would pick up the node''s local disk drives as
L2ARC.
To better clarify what I mean lets assume there is a 2-node cluster with
1sx 2540 disk array.
Now lets put 4x SSDs in each node (as internal/local drives). Now
2011 Jan 10
0
L2ARC and prefetched data.
Hi.
I can''t reach Brendan Gregg with this question (user unknown, he doesn''t
work for Oracle anymore?), so I''m sending it here:
FreeBSD users report much better performance and lower disk and CPU load
when L2ARC also holds prefetched data (l2arc_noprefetch = B_FALSE).
I was wondering what was the reason to avoid storing prefetched data on
L2ARC vdevs by default.
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2010 Jun 19
6
does sharing an SSD as slog and l2arc reduces its life span?
Hi,
I don''t know if it''s already been discussed here, but while
thinking about using the OCZ Vertex 2 Pro SSD (which according
to spec page has supercaps built in) as a shared slog and L2ARC
device it stroke me that this might not be a such a good idea.
Because this SSD is MLC based, write cycles are an issue here,
though I can''t find any number in their spec.
Why do I
2010 Jun 24
1
Gonna be stupid here...
But it''s early (for me), and I can''t remember the answer here.
I''m sizing an Oracle database appliance. I''d like to get one of the
F20 96GB flash accellerators to play with, but I can''t imagine I''d be
using the whole thing for ZIL. The DB is likely to be a couple TB in size.
Couple of questions:
(a) since everything is going to be
2011 Nov 08
6
Couple of questions about ZFS on laptops
Hello all,
I am thinking about a new laptop. I see that there are
a number of higher-performance models (incidenatlly, they
are also marketed as "gamer" ones) which offer two SATA
2.5" bays and an SD flash card slot. Vendors usually
position the two-HDD bay part as either "get lots of
capacity with RAID0 over two HDDs, or get some capacity
and some performance by mixing one
2010 Feb 20
6
l2arc current usage (population size)
Hello,
How do you tell how much of your l2arc is populated? I''ve been looking for a while now, can''t seem to find it.
Must be easy, as this blog entry shows it over time:
http://blogs.sun.com/brendan/entry/l2arc_screenshots
And follow up, can you tell how much of each data set is in the arc or l2arc?
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