CentOS - Jan 2017 - CentOS 7 and Areca ARC-1883I SAS controller: JBOD or not to JBOD?

Hi,

Does anyone have experiences about ARC-1883I SAS controller with CentOS7?

I am planning to have RAID1 setup and I am wondering if I should use
the controller's RAID functionality which has 2GB cache or should I go
with JBOD + Linux software RAID?

The disks I am going to use are 6TB Seagate Enterprise ST6000NM0034
7200rpm SAS/12Gbit 128 MB

If hardware RAID is preferred, the controller's cache could be updated
to 4GB and I wonder how much performance gain this would give me?

Thanks!
Peter

Haven't used Areca in a very long time, but with raid controllers the rule
is to use it in order to take advantage of the cache.
The performance gains will be more than significant, especially for writes.

hth

--
Sent from the Delta quadrant using Borg technology!

Nux!
www.nux.ro

----- Original Message -----
> From: "Peter Peltonen" <peter.peltonen at gmail.com>
> To: "CentOS mailing list" <centos at centos.org>
> Sent: Friday, 20 January, 2017 17:31:56
> Subject: [CentOS] CentOS 7 and Areca ARC-1883I SAS controller: JBOD or not
to JBOD?
> Hi,
> 
> Does anyone have experiences about ARC-1883I SAS controller with CentOS7?
> 
> I am planning to have RAID1 setup and I am wondering if I should use
> the controller's RAID functionality which has 2GB cache or should I go
> with JBOD + Linux software RAID?
> 
> The disks I am going to use are 6TB Seagate Enterprise ST6000NM0034
> 7200rpm SAS/12Gbit 128 MB
> 
> If hardware RAID is preferred, the controller's cache could be updated
> to 4GB and I wonder how much performance gain this would give me?
> 
> Thanks!
> Peter
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos

> The disks I am going to use are 6TB Seagate Enterprise ST6000NM0034
> 7200rpm SAS/12Gbit 128 MB
Sorry to hear that, my experience is the Seagate brand has the shortest MTBF
of any disk I have ever used...
> If hardware RAID is preferred, the controller's cache could be updated
> to 4GB and I wonder how much performance gain this would give me?
Lots, especially with slower disks. You can also leverage write back caching 
if you have a battery on the controller as well. There are countless frameworks
and one off utilities that can properly report on the throughput for various
patterns, set it up both ways and know for sure.

Not related to your question, but something to keep in mind: What type of
enclosure are you using? If you are using an engineered system your enclosure
will communicate with the controller. When a disk fails it's a pain in the
arse
to figure out where it exists physically. If you have an expander for example,
this gets even more challenging.

jlc

On Fri, January 20, 2017 12:59 pm, Joseph L. Casale
wrote:
>> The disks I am going to use are 6TB Seagate Enterprise ST6000NM0034
>> 7200rpm SAS/12Gbit 128 MB
>
> Sorry to hear that, my experience is the Seagate brand has the shortest
> MTBF
> of any disk I have ever used...
>
>> If hardware RAID is preferred, the controller's cache could be
updated
>> to 4GB and I wonder how much performance gain this would give me?
>
> Lots, especially with slower disks. You can also leverage write back
> caching
> if you have a battery on the controller as well. There are countless
> frameworks
> and one off utilities that can properly report on the throughput for
> various
> patterns, set it up both ways and know for sure.
>
> Not related to your question, but something to keep in mind: What type of
> enclosure are you using? If you are using an engineered system your
> enclosure
> will communicate with the controller. When a disk fails it's a pain in
the
> arse
> to figure out where it exists physically. If you have an expander for
> example,
> this gets even more challenging.
This is why before configuring and installing everything you may want to
attach drives one at a time, and upon boot take a note which physical
drive number the controller has for that drive, and definitely label it so
y9ou will know which drive to pull when drive failure is reported.

Valeri
>
> jlc
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
>

++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
++++++++++++++++++++++++++++++++++++++++

On 1/20/2017 9:31 AM, Peter Peltonen wrote:
> I am planning to have RAID1 setup and I am wondering if I should use
> the controller's RAID functionality which has 2GB cache or should I go
> with JBOD + Linux software RAID?
>
> The disks I am going to use are 6TB Seagate Enterprise ST6000NM0034
> 7200rpm SAS/12Gbit 128 MB
>
> If hardware RAID is preferred, the controller's cache could be updated
> to 4GB and I wonder how much performance gain this would give me?
if the controller's cache has battery or flash backed writeback 
protection, that should be in play whether you use it as jbod or 
"hardware" raid.   you'll find the biggest performance boost will
be on
OLTP type database operations where many small insert/update 
transactions are being done.... but, those drives are more of a bulk 
storage sort of drive, suitable for things like backup data, media 
servers, rather than database... dedicated database servers generally 
use higher RPM drives or nowdays, enterprise-grade SSD.



-- 
john r pierce, recycling bits in santa cruz

On 1/20/2017 10:59 AM, Joseph L. Casale wrote:
> Not related to your question, but something to keep in mind: What type of
> enclosure are you using? If you are using an engineered system your
enclosure
> will communicate with the controller. When a disk fails it's a pain in
the arse
> to figure out where it exists physically. If you have an expander for
example,
> this gets even more challenging.
this is my biggest gripe with roll your own 'whitebox' storage systems 
today...   you get a brand name server, like HP or Dell, with HP or Dell 
storage, and when a drive fails, the failure light on that drive comes 
on bright RED, so there's no QUESTION what drive is offline and needs 
replacing....    whitebox raid or HBA card, with generic SAS expander 
trays, or whatever?  good luck, implementing that failure mechanism is 
left as an exercise to the reader, without any  clue how to go about it.



-- 
john r pierce, recycling bits in santa cruz

On 01/20/2017 09:31 AM, Peter Peltonen wrote:
> I am planning to have RAID1 setup and I am wondering if I should use
> the controller's RAID functionality which has 2GB cache or should I go
> with JBOD + Linux software RAID?

I'd recommend testing the specific application that will run on this 
system.  It's not unusual for a system to preform well in simplistic 
benchmarks (like bonnie++), but not in real-world use. I recently 
conducted tests in which a MegaRAID controller handily outclassed 
software RAID under bonnie++, but fell short under better benchmarks 
provided by filebench:

https://plus.google.com/+GordonMessmer/posts/eSe6iNmk1Fs?sfc=false