

SSD Caching Using dm-cache Tutorial - 2bluesc
http://blog.kylemanna.com/linux/2013/06/30/ssd-caching-using-dmcache-tutorial/
The tutorial covers the basic steps to setup dm-cache on a Ubuntu 13.04 machine.
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yebyen
Thanks for this nice article!

I've had a Windows 8 laptop with the support for built-in SRT/RST/AcronymSoup
as it comes from ASUS/Intel, and I've been dragging my feet on setting up
flashcache because 1) I don't know what I'm doing, and 2) I don't want to
break the already existing Windows 8 support for this feature until I'm sure I
can get the same benefits from the SSD in Linux.

Also, 3) I was pretty sure I would have to use flashcache because it seemed
that nobody had written a good tutorial for any other method.

I just hate it when there's only one implementation of a new feature and it's
not well-supported by the distribution.

I still haven't tried your tutorial but it looks like you've paid careful
attention to all of the important details, like alignment and most importantly
"what do I do when I don't want to have this on my filesystem anymore"

Much appreciated.

~~~
2bluesc
The v3.10 kernel I used in the article also now supports bcache in the
mainline kernel which now makes that a compelling solution as well. I looked
at flashcache, but I maintain enough custom kernels for my job, don't want to
do that for my personal life as well. (Maybe if I was still in my Gentoo
obsession days...)

I think I'll checkout bcache in the future, since it's sitting there waiting
to be turned on with Linux v3.10. My only concern is whether or not I can just
add ssd caching to an existing filesystem, or if I need to copy all the data
to the newly created bcache/flashcache block device. With dm-cache it just
sits on top and makes the transition to (and from) a 10TB cached volume as
simple as a 1GB cached volume. No backing up the data somewhere and copying
it.

For personal use dm-cache seems to fit the bill, for now. My sights are really
set on the file system doing this more intelligently (think file level instead
of block level) then device-mapper ever could. I'm mostly waiting on this
btrfs to add hot-migration:
[http://www.phoronix.com/scan.php?page=news_item&px=MTM3Njg](http://www.phoronix.com/scan.php?page=news_item&px=MTM3Njg)

Now if this was a specific purpose server (ie database?) then maybe flashcache
or bcache would make a more compelling performance argument up front and
warrant the hassles they require.

