Improving IO with FlashCache
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Devator
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Published on 2012-11-15T16:22:02Z
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2012/11/15
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I have a server with 2 HDD's (2x 1 TB), running in RAID 1 (SW-RAID). I want to improve IO performance by using flashcache
. There are running KVM virtual machines on it, using LVM
.
Regarding this, I have the following questions:
- Will this even work?
flashcache
works for block devices, however these are all virtual machines with their own setup. - How much would I expect to increase performance? Most virtual machines run websites and some host games.
- How big does the SSD needs to be? Would having a bigger SSD increase performance since it's able to cache more files?
- What happens if the SSD dies? Would
flashcache
retrieve files from the traditional HDD and I could simply replace the SSD? - How much faster would
writeback
be in comparison withwritethrough
andwritearound
?
I have no access to a test system unfortunately, so could I install flashcache
on a live server without unmounting the the disks? I found a great tutorial here which I would be using.
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