SSDs in RAID 10 for Server

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NeoGohan

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Hey guys, I'm in a pickle. So, I'm building a RDS Server(formerly Terminal Server) that will basically just run applications for our users. I've always been interested in using SSDs in servers but not sure how reliable they are.

I would want a RAID 10 with hard disk drives but with SSDs, I have read that they lose trim when in RAID. Is trim that important that I should ditch SSDs for 10k rpm sas drives? I need to figure out the pros and cons of going to SSDs for RAID 10. I know TRIM is pretty important but if there's a way I can manually do what TRIM does another method, let me know, too.

Lastly, what ssds do you guys recommend for servers? I've read that ssds die pretty quick(several months) when they are used often. Is that true?

Thanks!
 
NeoGohan said:
Hey guys, I'm in a pickle. So, I'm building a RDS Server(formerly Terminal Server) that will basically just run applications for our users. I've always been interested in using SSDs in servers but not sure how reliable they are.

I would want a RAID 10 with hard disk drives but with SSDs, I have read that they lose trim when in RAID. Is trim that important that I should ditch SSDs for 10k rpm sas drives? I need to figure out the pros and cons of going to SSDs for RAID 10. I know TRIM is pretty important but if there's a way I can manually do what TRIM does another method, let me know, too.

Lastly, what ssds do you guys recommend for servers? I've read that ssds die pretty quick(several months) when they are used often. Is that true?

Thanks!
Click to expand...

How much space do you need? I have seen 32GB x25-e's go for $175 ea on ebay....saw that yesterday actually.

They are SLC so should last a lot longer than consumer level ssd's.
 
I'm looking to have at least 100GB just to be safe. It's basically going to be used for OS and applications.
 
you have not said what the server will be used for, so we dont even know if using SSDs will have any benefit at all for you.
 
ghost6303 said:
you have not said what the server will be used for, so we dont even know if using SSDs will have any benefit at all for you.
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So, the server that I am going to build will have users use remote desktop to connect to our RDS server to do their work. This server will host up to 40 users desktops at once so a lot of closing and opening applications will occur along with running standard user programs like Microsoft Office, web browser, PDF reading and creation, etc. People will be saving their files and work onto a file server that is network mapped to this server.

Thanks for helping.
 
If you only need 100GB, I think the x25e's should work well.

8 should give you ~ 120GB. They don't support trim anyhow. they are SLC. Probably exactly what you are looking for.
 
Thanks for the suggestion Robstar, but my server can only hold up to 6 2.5" drives. It's a Dell PowerEdge R715.

I understand that I can go SSDs, but my question isn't if I can, it's if I should since I last heard that SSDs in RAID lose TRIM support, which I think is important if I'm going to have many users using this machine. Basically, I'm not going SSDs in RAID 10 because it seems to me that TRIM is very important. However, if there is a way for me to do TRIM-like maintenance on these SSDs in RAID then please let me know as that is the only thing holding me back from going to SSDs.
 
Intel has a utility that will perform "trim like maintenance". I believe you can even schedule it with a .bat. The catch, I believe, is that once it's in an array the drives are no longer seen as SSD's at all. So the simple answer is that you are not going to see trim with a RAID array. The closest you will come is something like the garbage collection on the Indilix SSD's. But you shouldn't worry with the SLC disks. Trim is basically a moot point there. Honestly I wouldn't worry about it any way. I have yet to hear of anyone seeing their array degrade noticeably without trim. Sure your benchmark performance will drop off a little bit at the beginning but it will level out and it will still put anything mechanical to pure shame. Absolute beaten into the ground, blue in the face, pissed in the pants, tail between the legs, punished shame. All of this sweating people are doing regarding trim and RAID is beginning to drive me nuts. Even the JMicron drives beat the shit out of a VR in real world usage since they updated the firmware. Well TBH they did before too, it's just that they sucked wind when you were installing software. If you get the SLC drives do so because server loads are what they were made for. Honestly with RAID 10 I wouldn't worry about it. Get 4 x 120-160GB X25-M's, RAID them on a decent controller and don't think about it again until the controller dies on one of them.

EDIT: The Intel drives also do some kind of garbage collection. It's just not as aggressive as that on an Indilix controller. That's good for the kind of work load you are talking about since the GC can pig out on the drive's resources. I'm assuming that there will be some down time for these drives? When they aren't being hammered? Don't worry about it.
 
What's considered a decent controller? I don't know too much about raid controllers. Thanks for your help. That was the answer I was looking for.

What kind of maintenance would I have to do after setting up a RAID 10 with 4 X25-M's?
 
Probably one of the LSI 92xx cards. Or one of the Areca 18xx cards.
 
Robstar said:
How much space do you need? I have seen 32GB x25-e's go for $175 ea on ebay....saw that yesterday actually.

They are SLC so should last a lot longer than consumer level ssd's.
Click to expand...
Actually, total write cycle count and write amplification are more important. Going for SLC means stealing your wallet.

If you want high write endurance, the newer 25nm MLC has higher endurance anyway on small writes than the first generation X25-E with 50nm SLC NAND. Write amplification is highly dependent on controller firmware and available spare space.

So if you want high endurance, only use half capacity of your SSDs. So buying 4x Intel G3 160GB = 640GB and dividing by two = 320GB would be a decent setup.

RAID0 might give you more endurance, if you do not require absolute uptime. Backing up to a single HDD might allow you to use RAID0 on the SSDs instead.

Buying the old X25-E now seems like a bad choice money wise, especially with new X25-E using e-MLC instead of SLC, there seems very little reason to opt SLC at this stage, assuming you can wait for the G3s.
 
For RDC, you are looking for better latency, and 10K SAS drives aren't going to deliver what the SSDs will. You want to use the SSDs and you should be fine with MLC drives. Even with the degredation, you are still going to get better performance than a SAS array unless those Intel drives lose a HUGE chunk of their IOPS performance when they start reusing previously written cells. I haven't seen or heard of such performance penalties. You can look at the resource monitor and see how much data is being written to disk to get an idea of what you'll need. You have to look at the types of applications that your users will be accessing from the server.

I don't have SSD in any of my Citrix servers (2008 R2 with XenApp 6) but the disk access is pretty quick (15K SAS mirrored drives) for most tasks since windows is good at caching data and then the RAID controller is a caching controller as well. With 20 users actively working on a server I see little blips of activity on drives and the resource monitor doesn't show any significant activity either. We're talking I/O in the KB/s, not much at all. Logons probably generate the most activity (for your run of the mill MS Office application server), and with SSD you're accessing the data much faster and users will notice and appreciate that.

I can't say for sure if it's true that SSDs die in a few months. If the manufactures are to be believed then that rumor is pure bullshit, unless the person was running benchmarks all day long. A heavily used database server could probably kill a drive if it is constantly written to but a RDS server is not very likely to do that. Buy SLC if drive life is a concern but it costs way more.

My $.02. Good luck!
 
Dear OP,

Time-frame?
Exact figure of investment? only pay for disk or you require to pay for entire server+solution?

40 desktop users x 50 iops = 2000 Easily addressed by a single X25-E. Obviously I understand you want more than that due to various reasons.

Sample software listed, exact major list possible? Are you creating PDF using Adobe software or just generate from MS Office?

I don't have answer, but further info can help others in refining the proposals.
 
lightp2 said:
Dear OP,

Time-frame?
Exact figure of investment? only pay for disk or you require to pay for entire server+solution?

40 desktop users x 50 iops = 2000 Easily addressed by a single X25-E. Obviously I understand you want more than that due to various reasons.

Sample software listed, exact major list possible? Are you creating PDF using Adobe software or just generate from MS Office?

I don't have answer, but further info can help others in refining the proposals.
Click to expand...
this.

He'll probably be just fine with a mirrored pair of X25-E drives. One drive will do it for him but you do want some redundancy in there. RAID-10 is overkill with SSD for a TS box.
 
sub.mesa said:
If you want high write endurance, the newer 25nm MLC has higher endurance anyway on small writes than the first generation X25-E with 50nm SLC NAND.
Click to expand...

That is incorrect. I suspect you do not understand the term "write endurance", or perhaps you mean something else and are using the wrong term.

Write endurance has a specific meaning with SSDs. It means the number of times a flash memory cell can be written to before it wears out.

The write endurance for 50nm SLC flash can be as high as 100K writes or even more. Recent 34nm MLC flash has write endurance in the 3K to 10K range (although IMFT has a higher-grade version, "enterprise NAND", that can endure 30K cycles).

The most recent word I have seen on the 25nm MLC flash from IMFT is that the write endurance is about 3K cycles. Although they seem to expect that they will be able to get that figure up a bit higher as their processes improve.
 
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Hasn't Intel claimed that their enterprise 25nm MLC will exceed the write endurance on their 50nm SLC?
 
drescherjm said:
Hasn't Intel claimed that their enterprise 25nm MLC will exceed the write endurance on their 50nm SLC?
Click to expand...

I have not seen such a claim, and it would certainly be false. Also, I believe I read that the next generation Intel enterprise SSDs would use 34nm flash, probably the MLC "enterprise NAND" with 30K write endurance. I think it is only the consumer SSDs from Intel that will use the 25nm flash, at least initially.

Now, if they were to claim that the total amount written during the SSDs lifetime is higher for, say a forthcoming enterprise 120GB MLC SSD than a 32GB SLC SSD, then that may be true, since with more flash, you can write more. If the 120GB SSD were made with 30K enterprise NAND MLC, and the 32GB SSD used 100K SLC, then they would be able to write about the same amount over their lifetime (the 120GB would be slightly better), assuming similar wear leveling and write amplification algorithms. If the 120GB SSD had better wear leveling and write amplification algorithms, and more reserved capacity, then it may very well be able to write more over its lifetime than the 32GB SLC SSD.

But my point was mainly that the term "write endurance" was being egregiously misused in this thread. Write endurance has a specific meaning -- the number of cycles that a cell of flash memory can be written to before wearing out.
 
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SSDs would be great for a Remote Desktop server, since users will only be reading app files, not storing anything but user settings.
On the other hand, unless users systematically close their remote session, all these apps will still be running and won't have to be loaded again, so a HDD array would work just as well. Maybe check how many users you'll be serving and how they use Remote Desktop. I personally rarely closed my sessions when I ran long tasks like compilations that could take several hours.

If you want to go the SSD way, there is no choice in brand but Intel (4-6 times more reliable than any other brand, can't find the article again). Going with small 32 GB drives is not a good idea. Since you'll be introducing SSDs in that environment, make sure you have hot/cold spares or a HDD replacement solution so you are not to blame if something goes wrong. Backup the applications' user settings as well, so they can be restored easily.

P.S. Have you considered Virtual Server as well? For instance if you need to run legacy applications on different operating systems or versions of Windows. The OS and apps can be stored as images that load almost immediately.

EDIT: Found it! Return rates for SSDs:

- Intel 0.59%
- Corsair 2.17%
- Crucial 2.25%
- Kingston 2.39%
- OCZ 2.93%

Page 6 of http://www.hardware.fr/articles/810-1/taux-pannes-composants.html (in French)

RE-EDIT: If the RD server's drives or RAID go bust, just run the server from this USB stick, it has RAID and read perfs of 371 MB/s! ^-^
 
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Yes, OCZ has horrible failure rates, however, when using them for video editing and large file/content creation, they are superior to Intel SSDs, though they aren't as fast for OSes.

It's kind of a trade off honestly, a solid OS build should go on an Intel, but for video editing, OCZ should be used.
 
Red Falcon said:
It's kind of a trade off honestly, a solid OS build should go on an Intel, but for video editing, OCZ should be used.
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Actually, if you are thinking of sequential read and write speed, then a 256GB Crucial C300 would be better for video editing than the OCZ, since it will have higher sequential read and similar sequential write speed.

Or if you need even higher sequential write speed than a C300, a Samsung 470 SSD has the highest sequential write speeds of any single MLC SSD that I have seen.
 
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