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OT: 3-core AMD for Software RAID 1?

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Norman Willis
OT: 3-core AMD for Software RAID 1?
on Jun 29, 2011 at 9:03:07 pm

It may be OT, but I trust you guys' opinion more than anyone else.

We need a webserver. I have two choices. The budget option is to build a $250.00 kit from Tiger Direct with an AMD 3-core chip and 8GB RAM. If I put two 1TB drives in software RAID 1, will that give me basically about the same performance as I might get with hardware RAID 1 and a two-core CPU? (I probably don't really anything more than that, because the DSL upload speed is the real bottleneck.) Or is there a cheap RAID 1 card I could use for that?

Alternately, I could reprovision my existing Dell T3400 Workstation (with a PERC 6i RAID controller card) as a webserver, and build a new video editing machine with a Core i7. I would love that, but I probably don't really need it, and the budget is tight right now.

Norman Willis
http://www.nazareneisrael.org


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Norman Willis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 29, 2011 at 9:11:52 pm

Alternately, I could migrate my RAID controller card to the new Core i7, and let the existing CoreDuo Quad handle software RAID 1?

I am trying both to save money, and get a new Core i7 out of the deal (ha ha).

Any ideas would be sincerely appreciated.

Norman Willis
http://www.nazareneisrael.org


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Alex Gerulaitis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 29, 2011 at 10:03:58 pm

Software RAID1 is totally fine - there is such a low overhead with it, I don't think you'll notice any performance hit. Will it be Windows or Linux?

Alex (DV411)


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Norman Willis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 29, 2011 at 10:06:29 pm

Thanks Alex.

It will be a Windows server.

Please correct me if I am wrong, but there is a serious performance hit on software RAID 5? (Or, not so much?)

Norman Willis
http://www.nazareneisrael.org


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Alex Gerulaitis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 29, 2011 at 10:09:58 pm

[Norman Willis] "Please correct me if I am wrong, but there is a serious performance hit on software RAID 5?"

Yes, at least two hits: computational (if it's software) and disk throughput.

Alex (DV411)


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Norman Willis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 29, 2011 at 10:31:01 pm

Sorry if I am not getting it. How much difference between software RAID 1 and RAID 5 is there? (like, in percent?)

Norman Willis
http://www.nazareneisrael.org


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Alex Gerulaitis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 29, 2011 at 10:47:03 pm

You are asking hard questions. :)

RAID1 can't be compared to RAID5 directly because these use different number of drives: 2 for RAID1 (theoretically more than 2 is possible - but I haven't heard of anyone doing this except for me :)) and a minimum of 3 for RAID5.

Even if they could be compared, there is no single or simple answer percentage-wise: it depends on the (total number of) drives, the controller, and the performance profile: e.g. streaming vs. database server.

Each scenario will be different.

If we compare RAID0 or 10 to 5, then it's a little more straightforward (but still too many factors in play). On, say, 4 standard desktop 7200rpm drives and ICH10 (hybrid) controller, RAID0 will produce sequential read/write numbers of 400 to 500MB/s, and RAID5 - 350-450MB/s reads and 150-250MB/s writes. These numbers are for empty / unfragged volumes; performance will decline to about 50% of it when fragged/full.

Phew. :)

Alex (DV411)


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Norman Willis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 30, 2011 at 5:32:05 am

>> You are asking hard questions. :)

That's me (haha).

OK, I have been reading all day, and my head is about to bust. I thought I should ask your advice again before I drop cash (come morning).

I have an old Intel Core2 Duo E6850 @3.0GHz sitting around, that originally came with my video editing machine (before I upgraded it to a CoreDuo Quad). Will that be adequate to power software RAID 1 for a webserver that also does dynamic content generation (DotNetNuke/.aspx)? Our uplink speed will be 768K.

For hard drives I have 3 x Seagate Barracuda Green ST1500DL003 1.5TB 5900 RPM SATA 6.0Gb/s 3.5" Internal Hard Drives (Bare Drives). Two of them are for software RAID 1, and 1 is for a spare.

Are 1.5TB hard drives ridiculous? Seagate is claiming 750,000 MTBF on the 2TB models (that is, assuming they survive the shipping). That is something like 85 years of continuous operation???! If they will be around for that long, I thought maybe I should really get larger drives, so we can use them a long time (and still have a spare in case anything goes out)?

But my main question is if the CPU will handle both dynamic content generation and software RAID 1 sufficiently, or if I need an inexpensive RAID 1 card (and which one)?

Thanks again!

Norman Willis
http://www.nazareneisrael.org


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Alex Gerulaitis
Re: OT: 3-core AMD for Software RAID 1?
on Jun 30, 2011 at 10:05:57 pm

[Norman Willis] "But my main question is if the CPU will handle both dynamic content generation and software RAID 1 sufficiently, or if I need an inexpensive RAID 1 card (and which one)?"

There isn't much of a difference between software RAID1 in Win7 or Server 2K8 (R2) and hardware-based RAID1 with the exception of bootable volumes. Those can't be software-RAIDed if memory serves me right. You can stay with the software RAID1 on non-bootable volumes.

Don't know jack about dynamic content generation in webservers so can't answer any questions about that - sorry.

Alex (DV411)


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