[Gluster-users] Shared web hosting with GlusterFS and inotify

[Pablo Godel]

I also ran into this problem trying to share the document root with two
servers. It would be great to find a solution.

Emile, is your inotify approach working?

Pablo



On Wed, Sep 15, 2010 at 11:12 AM, phil cryer <phil at cryer.us> wrote:

> We're interested in this as well, as we will be serving our docroot
> from a GlusterFS share. Have you tried nginx? I have not tested this,
> but after your benchmarks it sounds like I need to. Your inotifiy
> script looks like it would work, but it wouldn't for me; we use
> GlusterFS so we can store ~70TB of data, which we can't copy to the
> regular filesystem. This is a big risk indeed - can you share your
> benchmarking method? Did you simply use ab?
>
> Thanks for the heads up
>
> P
>
> On Wed, Sep 15, 2010 at 9:58 AM, Emile Heitor
> <emile.heitor at nbs-system.com> wrote:
> > Hi list,
> >
> > For a couple of weeks, we're experimenting a web hosting system based on
> > GlusterFS in order to share customers documentroots between
> > more-than-one machine.
> >
> > Involved hardware and software are :
> >
> > Two servers composed of 2x Intel 5650 (i.e. 2x12 cores @2,6Ghz), 24GB
> > DDR3 RAM, 146GB SAS disks / RAID 1
> > Both servers running 64bits Debian Lenny GNU/Linux with GlusterFS 3.0.5
> > The web server is Apache 2.2, the application is a huge PHP/MySQL
> monster.
> >
> > For our first naive tests were using the glusterfs mountpoint as
> > apache's documentroot. In short, performances were catastrophic.
> > A single of these servers, without GlusterFS, is capable of handling
> > about 170 pages per second with 100 concurrent users.
> > The same server, with apache documentroot being a gluster mountpoint,
> > drops to 5 PPS for 20 CU and just stops responding for 40+.
> >
> > We tried a lot of tips (quick-read, io-threads, io-cache, thread-count,
> > timeouts...) we read on this very mailing list, various websites, or
> > experiences on our own, we never got better than 10 PPS / 20 users.
> >
> > So we took another approach: instead of declaring gluster mountpoint as
> > the documentroot, we declared the local storage, but of course, without
> > any modification, this would lead to inconsistencies if by any chance
> > apache writes something (.htaccess, tmp file, log...). And so enters
> > inotify. Using inotify-tools's "inotifywait", we have this little script
> > watching for local documentroot modifications, duplicating them to the
> > glusterfs share. The infinite loop is avoided by a md5 comparison. Here
> > a very early proof of concept :
> >
> > #!/bin/sh
> >
> > [ $# -lt 2  ]&&  echo "usage: $0<source>  <destination>"&&  exit 1
> >
> > PATH=${PATH}:/bin:/sbin:/usr/bin:/usr/sbin; export PATH
> >
> > SRC=$1
> > DST=$2
> >
> > cd ${SRC}
> >
> > # no recursion
> > RSYNC='rsync -dlptgoD --delete "${srcdir}" "${dstdir}/"'
> >
> > inotifywait -mr \
> >    --exclude \..*\.sw.* \
> >    -e close_write -e create -e delete_self -e delete . | \
> >    while read dir action file
> >    do
> >        srcdir="${SRC}/${dir}"
> >        dstdir="${DST}/${dir}"
> >
> >        [ -d "${srcdir}" ]&&  \
> >        [ ! -z "`df -T \"${srcdir}\"|grep tmpfs`" ] \
> > &&  continue
> >
> >        # debug
> >        echo ${dir} ${action} ${file}
> >
> >        case "${action}" in
> >        CLOSE_WRITE,CLOSE)
> >            [ ! -f "${dstdir}/${file}" ]&&  eval ${RSYNC}&&  continue
> >
> >            md5src="`md5sum \"${srcdir}/${file}\"|cut -d' ' -f1`"
> >            md5dst="`md5sum \"${dstdir}/${file}\"|cut -d' ' -f1`"
> >            [ ! $md5src == $md5dst ]&&  eval ${RSYNC}
> >            ;;
> >        CREATE,ISDIR)
> >            [ ! -d "${dstdir}/${file}" ]&&  eval ${RSYNC}
> >            ;;
> >        DELETE|DELETE,ISDIR)
> >            eval ${RSYNC}
> >            ;;
> >        esac
> >    done
> >
> > As for now a gluster mountpoint is barely unusable as an Apache
> > DocumentRoot for us (and yes, with htaccess disabled), i'd like to have
> > the list's point of view on this approach. Do you see any terrible glitch
> ?
> >
> > Thanks in advance,
> >
> > --
> > Emile Heitor, Responsable d'Exploitation
> > ---
> > www.nbs-system.com, 140 Bd Haussmann, 75008 Paris
> > Tel: 01.58.56.60.80 / Fax: 01.58.56.60.81
> >
> >
> > _______________________________________________
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> > Gluster-users at gluster.org
> > http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
> >
>
>
>
> --
> http://philcryer.com
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