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

[Valeri Galtsev]

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