zfs discuss - Jun 2009 - [?] - What is the recommended number of disks for a consumer PC with ZFS

I''m building my new storage server, all the parts should come in this
week.

Intel XEON W3520 quad-core
12G DDR3-1333 ECC ram
2*74G 15K rpm SAS for OS
8*1T SATA disks in raiz2 or stripe 2 sets of 4-disk raidz
32G Intel X25-E SSD (may mirror it later)
2*Intel 82574L NIC
Qlogic 4Gb QLE2460 FC HBA

I have 8 SAS ports plus 6 SATA ports on motherboard, with the above config, I
still have 2 SAS ports free to expand, I''m thinking of adding
Supermicro 2.5in mobile rack with SAS expander later using the 2 SAS ports or
add another SAS HBA.



You may want to replace i7-940 with XEON version and use ECC memory.

ZFS doesn''t like RAID controller, at least my old SCSI raid with BBU
cache. I had LSI megaraid 320-4x with onboard 128M BBU cache, the performance is
horrible no matter how I tweak it. I replaced the raid controller with LSI 21320
SCSI card, everything flies.
-- 
This message posted from opensolaris.org

> I''m building my new storage server, all the parts should come in
this week...
How did it turn out ? Did 8x1TB Drives seem to be the correct number or a couple
too many (based on
the assumption that you did not run out of space; I mean solely from a
performance / ''ZFS usability''
standpoint - as opposed to over three dozen tiny Drives).

Thanks for your reply,
Rob
-- 
This message posted from opensolaris.org

----- Original Message -----
> > I''m building my new storage server, all the parts should come
in
> > this week...
> 
> How did it turn out ? Did 8x1TB Drives seem to be the correct number
> or a couple too many (based on
> the assumption that you did not run out of space; I mean solely from a
> performance / ''ZFS usability''
> standpoint - as opposed to over three dozen tiny Drives).
It''s quite possible to stack up hundreds of drives for ZFS, just
don''t put them all in the same vdev. Say, you have 32 2TB drives, split
that into 4 RAIDz2 vdevs in the same pool, and both speed and safety will be
good. Also, add a couple of fast SSDs for the SLOG if you expect lots of sync
writes (NFS, iSCSI etc) and some other (cheaper?) SSDs for L2ARC to help out
reads. This is particularly important if you want your server to work well
during scrub (osol does NOT work well during scrub performance-wice unless you
use SLOG and perhaps L2ARC).

Vennlige hilsener / Best regards

roy
--
Roy Sigurd Karlsbakk
(+47) 97542685
roy at karlsbakk.net
http://blogg.karlsbakk.net/
--
I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er
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idiomer med fremmed opprinnelse. I de fleste tilfeller eksisterer adekvate og
relevante synonymer p? norsk.

> I''m building my new storage server, all the parts should come in
this week.
> ...
Another answer is here:
http://eonstorage.blogspot.com/2010/03/whats-best-pool-to-build-with-3-or-4.html

Rob
-- 
This message posted from opensolaris.org

You haven''t stated what you intend to use your pc for and what your 
requirements are. Without that I don''t see how anyone can come up with 
an optimal configuration. So... what do you plan to do with your pc?

Do you want the fastest performance and don''t care about anything else?
use all SSDs and add them as single vdevs without redundancy but make 
sure you have a good external backup.

Do you want really faster performance and care about uptime? Use all 
SSDs and add them in mirrored pairs.

Do you need a lot of storage space and don''t want to spend thousands on
SSDs? use the included ssd for your boot drive and set up a data pool of 
2x2 mirror.

I could go on and on. because there are many different uses for consumer 
pcs. For most people, a single ssd and a single data drive will be good 
as long as they have external backup.

Today''s consumer level HDDs are pretty fast. They get slow as they fill
up. If the drive is only half filled and defraged it will perform faster 
than if it was 90% full.

Unfortunately zfs doesn''t have a defrag utility yet so if performance
is
really a concern maybe short stroking it to half size might be good. 
Using the other half as a hot spare as you suggested seems interesting 
if the drive is in a redundant configuration.

If you really need performance so bad that you''re considering short 
stroking your drives just get more SSDs.

The gateway pc you linked to comes with 1 80 GB SSD and 1 1TB HDD.

In most configurations you''d install the OS on the SSD and use the HDD 
for data and that configuration will be good for most applications.

I don''t see the point of dual booting any more. If you want OpenSolaris
to be your main OS but want to be able to run windows there are other 
options like Wine and virtualization like VirtualBox.