[clug] Linux LVM or cache solutions for SSD + HDD

[steve jenkin]

A friend recently sent me a link about Apple "Fusion Drive".

 - it's an LVM type (CS: Core Storage)
 - concatenates, RAID-0 style, SSD & HDD drives
   - places O/S files in SSD [not sure how it keeps them there]
   - writes all files initially go to SSD
   - can trigger a migration to SSD by 2 reads (copy file twice), IIRC.
	[fuzzy on detail, how it triggers: reads or writes?]
 - seems to work with 128Kb blocks
 - maintains a 4GB 'free space' on SSD
 - Doesn't seem to need FileSystem hooks

Only available on Mac Mini and iMac models, not Macbook.

MSY have reasonable PC 'packages' below $1000, with extra $200 for a
Samsung 840-series 250GB SSD. I'm tempted :-)

What do Linux people use to lash SSD/HDD together?

 - manual allocation + symlinks, incl nightly scripts
 - overlay mounts of important dirs
 - something automatic that relocates stuff
	(how to check HDD 'use'. atime?)
 - bcache (?IIRC) or other SSD caching tool
 - an LVM or 'md' config
 - something a whole lot cooler??

Thanks in Advance.

cheers
steve

-- 
Steve Jenkin, Info Tech, Systems and Design Specialist.
0412 786 915 (+61 412 786 915)
PO Box 48, Kippax ACT 2615, AUSTRALIA

sjenkin at canb.auug.org.au http://members.tip.net.au/~sjenkin