Am Wed, 22 Mar 2017 15:12:36 +0000 schrieb Peter Humphrey <pe...@prh.myzen.co.uk>:
> On Tuesday 21 Mar 2017 22:50:04 Kai Krakow wrote: > > ---<8 > > > I'm combining this with bcache. That's a cache between kernel and > > filesystem that you put on SSD. Apparently, it requires > > repartitioning to map your filesystem through bcache (it has to add > > a protective superblock in front of your FS). So, a small SSD + > > bcache can make your complete 500GB spinning rust act mostly like > > SSD perfomance-wise. > > > > I think there's a script that can move your FS 8 kB forward on HDD > > to add that bcache superblock. But I wouldn't try that without > > backup and some spare time. But it is a performance wonder. > > > > Using 3x 1TB btrfs RAID + 500GB bcache here. The system feels like > > an SSD system but I don't have to decide what to put on a small SSD > > and what to put on big slow storage. Is just automagic. ;-) > > You have me thinking now. I have a couple of spare 1TB SSDs here, and > my workstation is a 12-core i7 running on a 256GB NVMe drive with 32 > GB RAM. > > Maybe I should put the SSDs into a RAID-1 to contain the system (the > same as they were in the old, now defunct box), then use the NVMe for > bcache. What do you think of that idea? I'm not desperately short of > space, but I've none spare either. I'm not sure if bcache can use NVMe at their full potential... Maybe head over to the bcache list and ask there. I think it faces some write serialization issues while NVMe should better work with multi-queue scheduler. If you're going to use mdraid, maybe better look into mdcache. But your results would be interesting. :-) -- Regards, Kai Replies to list-only preferred.
