As you note, seeks are going to be the biggest beneficiary of SSDs. Metadata operations tend to be all seeks (other possibilities include large memory mapped files, but that's a rarer use case), so if you can, run a filesystem that allows you to segregate metadata onto the SSDs, and use the spinning media for data. The catch would be that I'm not sure that Drobo supports it.
Skylar On 12/06/2016 12:35 PM, Craig Constantine 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 > [email protected] > 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 [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
