As a general rule, sequential streams (sustained read/write) are the bread and butter of spinning rust. SSD's eat random seeks for breakfast. The trick here, though, is whether the it's worth the extra money to get SSD over the 15k with only a gigabit ethernet connection. I'm inclined to say that if your workload is seriously random, you'd be better off with SSD, because random workloads won't get close to those speeds anyway. The one caveat here is if it's the same data over and over again, then a simple cache in front of 15k would probably outperform that. It's a delicate ballet of criteria. Either the SSD or 15k will crush the 7200's performance, that's for sure. SSD is also easier on power consumption and should, in theory, be more reliable (assuming you get good quality drives).
That didn't help at all, did it? Sigh... -Adam On Tue, Dec 6, 2016 at 3:35 PM, Craig Constantine <cr...@constantine.name> wrote: > Does anyone know off the top of their head, or have a reference for, > details or thoughts about NAS (network attached storage) performance with > SSD over spinning rust? > > I have a Drobo 5N that is currently using 7200rpm drives, and is on > gig-ethernet. I'm looking to squeeze more performance out of it and am > considering replacing drives with either SSD or 15krpm drives. I'm not > concerned about the cost (1Tb drives are big enough for this array), I > simply don't feel like performing the experiment with one, only to find out > the other option would do better. > > I suspect -- but am not sure how to measure this -- the constraint is with > seeking. The App I'm running on my local system does a huge amount of > read/write seeking all over the file system. So my hunch is that it's all > about the seek time. That leads me to think that steping up to 15krpm > drives, or to SSD, would be a bit win over the 7200rpm I have now. > > Other info... > > Drobo savy people: this drobo already has the add-on RAM cache installed. > > Sustained i/o: I've done a disk speed test (using Blackmagicdesign's Disk > Speed Test) and I currently get 72+MB write and 85+MB read from the NAS. If > I understand the test tool, this is a sustained write/read data stream, > because the tool is meant to test for video i/o performance usability. And > if my rusty math is right, gigabit ether converts to 128MB/s absolute > ceiling. ...therefore I don't think I have a problem (nor any room or > desire for much improvement) in terms of sustained i/o. > > -c > > _______________________________________________ > Discuss mailing list > Discuss@lists.lopsa.org > https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss > This list provided by the League of Professional System Administrators > http://lopsa.org/ >
_______________________________________________ Discuss mailing list Discuss@lists.lopsa.org https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
