[OPLINTECH] RAID 5 vs. RAID 10 on a file server

Wed Dec 2 12:23:56 EST 2015

http://www.adaptec.com/en-us/solutions/raid_levels.html

That's a good write-up and comparison of the various types of RAID. Each
type has it's own characteristics, strengths, and weaknesses and you really
need to assess your own scenario and requirements to determine what type of
array will work best for your particular needs.

In my own experience, I do use RAID 5 and I use RAID 1. On a purely comfort
level, I've always felt the most comfortable using RAID1...simply because
ALL of the data resides in a complete and usable form on a single drive. In
an absolute catastrophe with absolutely critical data, I could even take
one failed/failing drive out and stick in into a plain old workstation for
recovery/repair efforts or even send it off to be repaired, if I needed to
go to that level (I never have). I've never lost data on a RAID1.

On the other hand, I *have* been bitten by a RAID controller with firmware
that didn't safely handle a RAID5 array with a marginal drive. It pretty
much ruined the whole array. Twice. Each time, I had to rebuild the array
and recover the data from backup. Fortunately, it was just my own in-house
company server and didn't store irreplaceable data. But still a PIA and
I've since then been a little gun-shy of arrays that require multiple
drives to store a single set of data (basically, anything that isn't a
RAID1).

But I still do usually use RAID 5 because it has a good balance between
reliability, performance, cost, and allows the creation of a large single
array. You've given me some food for thought, though. With hard drives
having commodity-level prices these days, maybe it's time to take a closer
look at 10.

WRT RAID10, it does seem that 10 performs better for both reads and writes,
although RAID5 can perform equally well in an environment with more reads
than writes. RAID 10 can also potentially sustain more drive failures
before data loss vs RAID 5. But you pay more for 10. There's lots of
technical analysis and info about 10 vs 5 (and RAID in general), if you
Google for it.

Bottom line, you'll have to figure your own needs and find the array that
best suits your specific balance between reliability, performance
characteristics, and cost. Also, always use a hardware array. Always have a
hot spare available And always use ECC RAM!

$.02,
Chad

______________________________
*Chad Neeper*
Senior Systems Engineer

*Level 9 Networks*
740-548-8070 (voice)
866-214-6607 (fax)

*Full IT/Computer consulting services -- Specialized in libraries and
schools*

On Wed, Dec 2, 2015 at 11:10 AM, Jim Lack <J.Lack at rrpl.org> wrote:

> Thanks Jessica.  I guess I’m at the other end of the spectrum.  All our
> servers have RAID 5 setups and I’ve never come across an issue of having
> downtime.  Sure, I’ve had drives go bad but the systems keep plugging away
> until I get a replacement drive in.  I just don’t know if there is a huge
> benefit if I move to RAID 10.  Thanks for your input!!
>
>
>
> *From:* Jessica D. Dooley [mailto:dooleyje at adamscolibrary.org]
> *Sent:* Wednesday, December 02, 2015 11:01 AM
> *To:* Jim Lack
> *Subject:* RE: [OPLINTECH] RAID 5 vs. RAID 10 on a file server
>
>
>
> Hi Jim,
>
>
>
> I can’t speak to the reputed performance benefits of RAID 10, since I’ve
> never used it, but I have four servers, including two domain controllers,
> running RAID 5, and I would never choose that configuration again. I have a
> virtual host and NAS box running multiple instances of RAID 1, but not
> configured for striping. RAID 1 with a hot spare would be my configuration
> of choice in the future. The servers configured with RAID 5 have failed on
> more than one occasion; even with backups, it’s a significant interruption.
> I’d be interested to hear if anyone has committed a large environment to
> RAID 10, and has seen noticeable performance benefits. Our domain
> controllers and member servers also double as file storage, with DFS
> replication configured. I’d downvote RAID 5 on reliability alone – fwiw.
>
>
>
> Thanks,
>
>
>
> Jessica D. Dooley
>
> IT Specialist
>
> Adams County Public Library
>
> 937-587-2085
>
> dooleyje at adamscolibrary.org
>
>
>
> *From:* Jim Lack [mailto:J.Lack at rrpl.org <J.Lack at rrpl.org>]
> *Sent:* Wednesday, December 02, 2015 10:43 AM
> *To:* oplintech at lists.oplin.org
> *Subject:* [OPLINTECH] RAID 5 vs. RAID 10 on a file server
>
>
>
> I need to replace my current domain controller with a new server.  The
> server also acts as our main file server.  Our current server is set up
> with two drives, configured in a RAID one setup which houses just the OS
> (Windows Server 2008).  We have three additional drives set up with RAID 5
> which houses all of our user files.  We also have an additional drive as a
> global hot spare.
>
>
>
> I’m wrestling with the option of using RAID 10 on our new server (someone
> suggested it).  Do I sacrifice a couple of drives in RAID 10 for
> performance or should I just stick with the RAID 1 (OS) and RAID 5
> configuration?  I’m just wondering if there will be a big benefit going
> with RAID 10.  There’s a lot of smart people on this list and I value your
> opinions.  Let me know your thoughts
>
>
>
> Thank You,
>
>
>
> Jim Lack
>
> Technology Support Manager
>
> Rocky River Public Library
>
> 1600 Hampton Rd.
>
> Rocky River, OH  44116
>
> 440-895-3765
>
>
>
> _______________________________________________
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> http://lists.oplin.org/mailman/listinfo/oplintech
>
>
>
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