[Linux-cachefs] looking for cachefs info/faq and benchmarks

[Mitch Crane]

Hi All!

I work for a high performance solid state storage company.  We're interested in using our device to cache NFS and possibly productizing that solution.  Our device presents as a block device on linux, so I would prefer to use FS-cache + cachefs (instead of cachefiles).  Is there any info or a FAQ around on setting up block device based caching using cachefs, as mentioned in the PDF?

Currently I am running FS-cache + cachefiles on centos 5.3 with 2.6.31.2 from kernel.org.. after downgrading nfs-utils (see notes below) and installing cachefiles-0.9 I have mounted my block device (formatted ext3, with xattr turned on) and I have modified /etc/cachefilesd.conf to point to a directory under that mount point.  I believe this is working, as I can see "cache" and "graveyard" being populated under that directory.. and dmesg tells me:

FS-Cache: Cache "mycache" added (type cachefiles)
CacheFiles: File cache on xxx registered

However, when I attempt to run benchmarking tools bonnie++ and fio, it looks like there's no benefit.  I believe this may be due to the nature of the benchmarking tools, but perhaps I just need to invoke them with the correct arguments?  Has anyone done any work towards setting up benchmarks that show the benefit of netfs caching?  Ah, it also looks like no files or subfolders were ever placed under "cache" or "graveyard".. maybe it's not working after all?

thanks a lot!
Mitch.



notes:
/// to downgrade nfs-utils and allow option "fsc"
# rpm -qa|grep nfs-utils
# rpm -e /// whatever u found there.. and whatever else needs to go, like the gui front end stuff
# wget ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Client/en/os/SRPMS/nfs-utils-1.0.9-16.el5.src.rpm
# rpmbuild --rebuild nfs-utils-1.0.9-16.el5.src.rpm 
# rpm -ivh /usr/src/redhat/RPMS/x86_64/nfs-utils-1.0.9-16.x86_64.rpm 

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