windows - Recommended RAID5 stripe size?
2014-07
Pentium100
I have a RAID5 array built from 4 1TB drives. I initially set the stripe size to 1M since I will be storing large files (much larger than 1MB). The NTFS cluster size is 64KB (largest possible). However, seeing the statistics made me reconsider my choice.
The software is relatively stupid and only has on 1 thread with QD=1, so for reads (this array will be mostly read) I will get an SSD and use that as cache. I won't be using that for writing, leaving only the internal cache of the controller (Adaptec 5805Z).
Still, I would like to get the best performance from this array.
So, the statistics (I can see them using Adaptec Storage Manager) say that for reading, 64KB, 128KB and 256KB are most common with 128KB taking first place (the software reads in 128K blocks). There were zero 512K or 1M reads. With writes, 256K is most common, 128K taking second place.
The question: Will changing the stripe size to 256K or 128K (or lower) speed up the array considering the statistics? Would that slow down the rebuild of the array?
reach3r
From your own data it should already be rather obvious to chose the most used chunk size. From the data you presented I would go for 128K (assuming more reads than writes).
This will reduce the wasted time on reads & writes significantly. How this turns out on your real world performance however is another story and depends heavily on the the type of load. With very flat queues the difference will probably not be huge.
For reference: There is an answer (and comment) to a different RAID-related question here on superuser which gives some good basic understanding of how to choose stripe size: http://superuser.com/a/647385/321113
Also on serverfault: http://serverfault.com/a/517251
Both of these clearly state that if you know which size your application(s) mostly use (which seems the case with the given statistics) you should go for these.
XHR
I'm going to be building a new system soon and I'm willing to spend a few more dollars to improve my hard drive performance. This will be a general use system so I just want to see HD intensive tasks in general go faster whether it be booting, application loads, game loads, maybe video editing, whatever.
My initial thought was to just buy 2 WD Raptors, RAID-0 them together and then just get a regular 1TB+ 7200 SATA drive for storage. The raptors would be my OS drive and all my installs would go there. I could perform whatever work I feel like on the OS drive and then when done move it over to the storage drive. Thus, its not too big a deal if one of the raptors failed, I would just have to reinstall everything.
Thing is, in reading some reviews, not everyone is impressed or notices speed improvements. This gets me to look at other options and honestly there are so many that it seems almost impossible to know what the best is for a medium price range.
SSD's have crazy differences in speeds between manufacturers and models, in the hundreds of Mbps! They also scare me right now, various reports of weird behavior like application freezes and such. I think I've actually experienced this on my SSD Eee netbook, though I can't confirm its the SSD's fault. Maybe the more expensive models don't have this issue. SAS 15k drives are comparable to the raptor's in cost and have better performance but it looks like a decent controller card will run you 200-300 easy.
Honestly right now I'm considering just getting a couple 1-1.5TB standard 7200 drives and raid-0 them together. It would be a huge waste of space as I have no use for that much room for an OS drive but it actually seems like a decent idea as I can probably do that for under $200 and still get a performance boost. Would it be slower than a single raptor (price is about the same at this point), hard to know really unless someone does a side by side comparison. People have done reviews I know but they get outdated fast as speeds and cache sizes improve on a regular basis.
I guess a 100% certain answer to the best combination for your money is pretty much impossible as nearly every combination out there amongst various models and types would need to be evaluated. So I guess I really would just like to get some insight into what generally will be a performance boosting setup for a mid range price (200-500). Thanks.
user10762
I have never found raid arrays really make that much of a positive performance boost for every day use. They certainly don't improve access times and that is what you tend to notice most in general use. I would also avoid raid-0 unless you don't care about the data being stored.
An SSD is the way to go to get a noticeable speed boost. Use a modest sized (60-128GB) one for a boot drive and a larger mechanical drive for bulk storage. If you want your games to load faster they should be kept on the SSD in which case you might want to get a larger drive (120GB+).
Almost any fairly recent SSD should be OK but Intel is best followed by drives based on Samsung or Indilinx controllers (Samsung are probably safer and Indilinx slightly faster). Cheaper drives based on JMicron controllers are OK only if you are on a very tight budget. If the price is cheap and there is no mention of the controller then assume it is JMicron based regardless of how impressive the specs might seem.
John T
The Intel X-25M fits well into your budget and has had great reviews. Even Linus Torvalds has been impressed with his Intel SSD. The X-25E performs better but only provides 32GB space, at a fairly higher price. If you choose a SSD, I'd only keep the OS on it and programs you use frequently that require high data transfer speeds. Other programs can be installed to a seperate 7200rpm disk.
check out tomshardware hard drive benchmarks. they benchmark all kinds of different drives from 3.5" to SSDs. There is also price included beside each one.