On Wed, Jan 13, 2016 at 01:28:57PM +1100, Trent W. Buck wrote: > AFAICT the only reason SSHDs exist are: > > * Windows has nothing like bcache/l2arc; or
it does. it's called ReadyBoost. Compared to bcache/flashcache or L2ARC for ZFS, it sucks. You can't just tell Windows to use an SSD (or partition thereof) to cache an arbitrary disk....well, in theory you can but in practice Windows itself decides whether that option will be available by its own inscrutable and undocumented method. I discovered this just last week after upgrading my win7 games box to have an SSD as a boot disk, decided to try ReadyBoost for my main 2TB steam library drive (not an SSHD) so made a 40GB partition for it. No matter what I tried, I couldn't get windows to make the option available in its Disk Manager GUI - it was there, just greyed out. I gave up and expanded the main partition...will have to manually move big games to the fast SSD, which works nicely - witcher 3 loads much faster off the SSD. More importantly, save games load in about 25 seconds rather than 60-90 seconds (which is really annoying when you die repeatedly because you thought attacking a royal griffin seemed like a good idea, 90 seconds to load the save, 15 seconds to die again while trying to run away, repeat until you succeed or rage-quit) Microsoft seems to have abandoned the ReadyBoost idea. and they seem to be confused about what SSD caching of hard disks is good for - their documentation is all about how it might help on low-memory machines (<4GB), presumably because they don't have enough RAM to cache large chunks disk in RAM. as bcache etc on linux prove, SSD caching is beneficial even on machines with lots of RAM. windows is so damn primitive and restricted. i can't understand how anyone could possibly think it's any good or that it makes a decent desktop environment. it's almost unusable in its awful crappiness. i'm glad i only have to use it as a games launcher. interestingly, i don't even have to use my KVM to switch to the windows box any more if i don't want to - steam's in-home streaming feature means that in addition to running native linux games on steam, i can "stream" windows-only games from my win7 box. that means it executes on windows but displays on my linux box in either full-screen or windowed mode. would probably suck on wireless but there's no noticable lag or performance loss on a wired gigabit network. i'm kind of amazed at how well it works. they built this feature to support their steamlink product, a box with an HDMI port running linux to plug into a TV in the lounge room and stream games over the LAN from Windows, Mac, and Linux machines running steam. > * My computer only has one disk bay. (you don't really need a disk bay for an SSD. just a sata port plus data and power cables. and if you wanna get fancy you can sticky-tape it to the side of the case :) > > That is, if you have a commodity server, > you're much better off buying the HDD and SSD components separately. > > (Am I wrong?) a good fast, large SSD will be better. more expensive too. but given that the SSHDs i bought were roughly the same price as non-SSHDs, i don't see any harm and some potential benefit in using them on linux. 8GB cache isn't much but it "just works" without any hassle or configuration. it's giving me some SSD caching on my ZFS 'backup' pool without having to add another SSD to the same andr dedicate an SSD partition to the task. BTW, the Transcend SSD370s are pretty good value at the moment. I bought a 256GB for $125. 512GB is $261. Specs are surprisingly good for the price...not as good as, say, the Samsung 850 Pro, but they cost $188 for 256GB and $333 for 512GB. but if you're not in a hurry to get an SSD, rumour has it that there will be significant increases in capacity AND reductions in price on SSDs this year. also BTW, this article on slashdot from a few days ago was interesting: http://hardware.slashdot.org/story/16/01/10/068211/ocz-revodrive-400-nvme-ssd-unveiled-with-nearly-27gbsec-tested-throughput no price was mentioned, but it's an M.2 (X4 PCI-e variant) SSD getting about 2.7Gb/s reads and 1.6Gb/s writes. plugs into an M.2 slot on a motherboard or PCI-e adaptor with one or two M.2 slots are reasonably cheap. available in sizes from 128GB to 1TB. will probably turn out to be unreasonably expensive, but should serve to push down the price of lesser SSDs. and it's a sign of things to come even for budget-conscious geeks like me over the next few years. all i want is a pair or two of 5 or 10TB SSDs approximating those speeds for about $100-$200/drive. that's not too much to ask, is it? that'd make a nice ZFS pool. at a guess, gear like that may be only 3 years away. craig -- craig sanders <[email protected]> _______________________________________________ luv-main mailing list [email protected] http://lists.luv.asn.au/listinfo/luv-main
