My ramblings on the stuff that holds it all together
Nexentastor, When 1Gb just isn’t enough
I have been trying to get my Nexentastor SSD/SATA hybrid NAS working this last week and I’ve found that the web UI grinds to a halt sometimes for me, I couldn’t find a UNIX ‘top’ equivalent quickly but the diagnostic reports that you can generate from the setup menu command line did indicate that it was short of RAM.
The HP Micro server I am using shipped with 1Gb of RAM, and normally that would be fine for a file-server/NAS but I’m thinking that Nexentastor does a fair bit more and is based on OpenSolaris rather than a stripped down Linux or BSD; the eval guide says 768Mb is enough for testing, 2Gb better 4Gb ideal so I was already pushing my luck with 1Gb for any real use.
So, I bit the bullet and ordered 8Gb of RAM for the server, which is the maximum you can install – ironically this cost the same amount as I paid for the whole Microserver in the 1st place (after the cash-back deal) but that’s reflective of the fact it only has 2 memory slots so I had to opt for the more expensive 4Gb chips.
I went for 8Gb as at some point I will probably re-run my experiments under ESXi and deploy this host as a part of my management cluster for the vTARDIS.cloud.
I am also booting the OS from a USB flash-drive – I had several 2Gb units but it wouldn’t install to them as they didn’t have quite enough space, so I’m using an 8Gb flash drive to hold the OS – this isn’t the most performant drive either so any swapping will be further impacted by the USB speed.
I’m Pleased to report that the 8Gb RAM upgrade has resolved all the problems with navigating the UI, and should also yield further I/O performance as the Nexentastor software uses the extra RAM as extra cache (ARC) as well as the SSD (L2ARC) – there is a good explanation of that on this blog post.
I’m going to post up my I/O benchmarking when I have some further wrinkles ironed out – in the meantime there is an excellent post here with some example benchmarks running Nexentastor in a VM on a slightly more powerful HP ML110 server.