CPU speed and memory size/speed vs Unraid file serving performance


shawn

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I'm looking for benchmarks on how differences in CPU and memory affects file serving performance, eg CPU PassMark vs MB/s, or memory size/speed vs MB/s. I'd like to build a new Unraid server for file serving only, so if it doesn't make much difference, I can keep costs low.

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Agreed, and you aren't going to find a benchmark quite like what you are looking for.  Since unRAID doesn't need a lot of CPU for basic NAS duties it quickly ramps from not working well to working well at low CPU levels.  You can build a basic NAS with a Celeron (or even a Atom), though personally I'd start with Pentium G3258 or G4400.

 

Note - quality network adapters and modern high capacity hard drives are just as relevant to overall NAS performance as the CPU.

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Agree -- if you're using it purely as a NAS, virtually ANY modern CPU will do fine.

 

I have 3 servers (plus a 4th for "experimentation" that doesn't contain any data I care about) => and my favorite of the bunch (not the highest capacity) is my trusty old SuperMicro X7SPE-HF-D525 based unit ... which uses an Atom D525 processor.  Completely quiet, VERY low power (idles at 18w with 6 drives), and as a NAS it's as fast at file serving at any of my other much-more-powerful servers.

 

I would not, however, upgrade this one to dual parity, as the impact of that 2nd parity calculation is indeed a significant bump in CPU demands.  But I'd say any CPU that scores 2000 or better on PassMark will be just fine for NAS duties.  Even low-end current generation Pentium and Celeron CPU's score well over that.

 

Note, however, that it's not unusual for folks to later decide to "do a bit more" with their UnRAID systems -- so you might want to look at CPU's in the 4000+ PassMark range just to provide a bit of "headroom", in case you later decide to stream a transcoded Plex stream or two  :)

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I'm going to be the counter opinion and say I am unable to max out transfer speeds on my Atom D525 system. I chased down performance issues and finally gave in and bought a more powerful Xeon D system (en route, unknown if it will really help). Max write speeds to the SSD cache from another powerful SSD over Gig Ethernet was still ~25MB/sec

 

That said, Patrick, the owner of Serve the Home, is decommissioning a nice Atom 2750 system with RAM for a spectacular price. I would have jumped on that had my Xeon D-1521 not gone on fire sale over Cyber Monday.

 

https://forums.servethehome.com/index.php?threads/las-vegas-colo-decommission-thread-much-fs.12199/

 

 

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Serving files is mostly about disk and network speed and doesn't require a lot of CPU. Calculating dual parity does require some CPU so if you intend to have that then maybe something to consider.

 

How do we get dual parity now?

Edit: I just saw it's a beta feature in unRAID Server Release 6.2.0-beta18. Does it seem reliable yet?

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Serving files is mostly about disk and network speed and doesn't require a lot of CPU. Calculating dual parity does require some CPU so if you intend to have that then maybe something to consider.

 

How do we get dual parity now?

Edit: I just saw it's a beta feature in unRAID Server Release 6.2.0-beta18. Does it seem reliable yet?

6.2 hasn't been a beta for quite some time. What version of unRAID are you running anyway?
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Serving files is mostly about disk and network speed and doesn't require a lot of CPU. Calculating dual parity does require some CPU so if you intend to have that then maybe something to consider.

 

How do we get dual parity now?

Edit: I just saw it's a beta feature in unRAID Server Release 6.2.0-beta18. Does it seem reliable yet?

 

As trurl noted, 6.2 hasn't been Beta for several months.  The current stable release is v6.2.4 => and Yes, dual parity is very reliable, and clearly provides MUCH better fault tolerance than a single parity system.

 

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6.2 hasn't been a beta for quite some time. What version of unRAID are you running anyway?

 

That's interesting. I haven't checked the official releases lately but I didn't see obvious references to dual parity on lime-technology.com at a glance. This seems like an important new feature. If you guys didn't point it out, I wouldn't know anything about it. I think they could advertise it more prominently on the website.

 

I'm still on 5.0.6. Some tips on upgrading to the latest version? I tend to avoid upgrades unless there are new features I want.

 

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I'm still on 5.0.6. Some tips on upgrading to the latest version? I tend to avoid upgrades unless there are new features I want.

Even if you only want a NAS, V6 is well worth the upgrade. It has many features you want, you just don't know it. Notifications, improved diagnostics, better support from the forum to name a few.
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What about memory size and speed, what would be too small or too slow for say dual parity?

That would mostly depend on the number of disks you intend to use.

 

What about 10 disks, or 20?

 

It's a good feature no matter how many disks you have; but certainly with 10 or more it's a very good idea.  The primary benefit is that if you have a disk fail, and are doing a rebuild of that failed disk, the rebuild will still be successful if a 2nd disk fails while it's in progress.    The fact the system is dual fault tolerant does NOT mean you should wait for 2 failures before replacing the disks !!  8)

 

Remember that RAID -- regardless of how fault-tolerant it might be -- is NOT a substitute for backups.  You should still have backups of all of your data (or at least any data you don't want to lose).    Some folks don't bother with backups -- a risk I certainly don't recommend -- but if you don't have backups I'd think you absolutely would want dual parity ... no matter how many data disks you might have.

 

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... I'm still on 5.0.6. Some tips on upgrading to the latest version? I tend to avoid upgrades unless there are new features I want.

 

That's not an unrealistic approach.  In fact, I still have one server I leave on v5.0.6 because it's got a fairly low-end CPU (Atom D525) and the CPU demands of v6 are appreciably higher than with previous releases.  That particular server is rock-solid and will likely serve me well for years to come ... and will almost certainly never be upgraded.

 

My other servers are all on v6, as they have significantly more "horsepower".  I agree that v6 has some very nice feature improvements; but quite candidly v5.0.6 with UnMenu does everything I need for a NAS, and I don't miss any of the newer features with it.

 

 

But since you're building a new server, you'll undoubtedly have plenty of "horsepower" for v6, so that's what I'd recommend -- primarily for the dual parity support; but also because it does have an improved GUI.

 

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What about memory size and speed, what would be too small or too slow for say dual parity?

That would mostly depend on the number of disks you intend to use.

 

What about 10 disks, or 20?

For 10 disks any relatevely recent dual core CPU is enough, eg, AMD A4,  any dual core Intel Sandybridge and newer, even most Conroe's are enough. 

 

For 20 disks recommend at least a dual core Sandybridge Pentium or better, eg G2030.

 

For the basic NAS functions 4GB of RAM is enough.

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