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LockDown32Flag for United States of America

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SSD vs 15k SAS in entry level server

Yes this question has been asked a million times but I am going to ask it again. Everything depends on what the server is doing and running and everyone is different. I am looking for a "generic" answer. It is going to be an entry level server. Windows 2012 something. No SQL or intensive database. Just a general purpose server for 20-25 users. I am going to run a Raid 5. That being said which would be better, SSD or 15k SAS?

As kind of a side question I have heard that longevity is a problem with MLC SSD drives. Is that true?
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Scott C
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The whole reason the question came up again was because of cost. A 480GB Intel SSD (Pro 2500) is down to $210. A Seagate Cheetah 450GB 15k SAS drive is $205. The is no price difference. Cost can be removed from the equation. I should have included that above.
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Thanks Rindi. Your comment about not being able to use any SSD in a server is server 101. Not only do you need to get a SSD that is supported by the Raid controller but you need to get a Raid controller that is supported by the motherboard. Hence the server compatibility list.

"Larger capacities and the disk are cheap" really applies more to the SAS and SATA and not so much the SSD drives. You reach a point with the SSD drives where the bang for the buck disappears. I have never had a Raid 5 do anything but run. Even rebuilding was simple but is might be because I use Adaptec. What put such a foul taste in your mouth about Raid 5?
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This whole thing has gotten kind of interesting. All the articles I have read say that it isn't necessarily that Raid 5 is bad it is that there might be better alternatives like Raid 10 or Raid 6. This is all predicated on larger drives being so cheap. Well... about the only larger drives that are truly cheaper are the SATA 6Gb/s. A TB WD RE is $134 at Newegg and that is cheap but they don't perform nearly as well as SAS 15k or SSD and both of those drives are still at a premium to where Raid 5 would actually make sense. Is the only objection to Raid 5 the unhandled read error (or what ever they call it)?

   Not too many entry level servers need TB after TB of storage but what they could use is performance....
Personally, I see no issues with RAID5.  It provides a good price/performance mix, and you get redundancy from any one failed drive.  RAID10 is definitely faster, and is what I recommend for my write-intensive database customers, but overkill for a "entry-level" system.  RAID6 provides dual redundancy, but can be slower still.  

I would definitely think about avoiding any RAID array implemented in software -- stick with hardware RAID for performance reasons.  Of course, this adds to the price, and takes us back around to the "entry-level" designation.

If it were me, I would look at the following:
1) CPU clock speed: This is still king when it comes to speed.  You won't need lots of cores, so go with fewer cores and faster clock speed if possible.  Think 3.4GHz or faster.
2) Memory: Memory is second for performance.  More RAM allows for more caching, which cuts down on the disk reads needed -- thus improving performance.  Memory is also pretty cheap right now, so think 32GB or more.
3) Disk: Disk usually comes third, because when memory runs out, you have to go to disk.  Again, hardware RAID and fast drives are important, but less so if you've properly done 1 & 2 the right way.
4) All other features:  Redundant power supplies can be important in case a UPS fails.  (Yes, I have had UPS units fail, and YES, my servers with redundant power supplies have survived this failure.  I also had my desktop UPS fail last week, and that computer went down hard.)  Disk size is important, but you can easily migrate data to a NAS and save a LOT of costs.  Power utilization is also important for small facilities -- will they need a dedicated circuit?  A new UPS?  A dedicated cooling system?  These operational costs can also add up.  Also pay attention to the noise profile.  I once purchased a network security appliance for my small office -- but the fans ran at such a high speed and such a  loud whine that I was NEVER able to use it.  It was in the rack for about a year before I took it out & sold it on EBay -- losing money on the deal.  So, don't ignore the noise factor, especially for a small office.

Now, look at the servers within your budget, and start making trade offs.  Save money where you can, and spend it where you want.  Having too much of a budget is a good thing sometimes, but it can lead to buying a box which is a LOT bigger and more costly to run.
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Only objection of RAID 5 in a low write situation like this is the chance of it fasiling to rebuild completely due to bad blocks on a surviving disk plus the write hole which is a risk on any controller that  doesn't have battery backed write cache.
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