Thanks Ezra. Actually, I believe it was your talk at RailsConf that inspired this. So thanks again! I suspect that, for the short term, with only say 10-20 servers per GFS disk it may be ok. If that all works out and we scale up then I'm sure we'd go SAN. Thanks for the info on the contextual symlinks, that's very cool.
How does GFS handle immense volume, in terms of say you have these 20 servers writing their logs to a single "disk", and let's say you're being slashdotted/dug(digged?), so there's tons of logging (I guess enough to overwhelm GigE, but I haven't calculated to see if that's realistic to overwhelm in such a case), how does GFS behave? Obviously I'll have to test all this, but hoping to short circuit any insurmountable problems or bad usage, etc. On 6/7/07, Ezra Zygmuntowicz <[EMAIL PROTECTED]> wrote: > > > > On Jun 7, 2007, at 10:43 PM, Chris Bailey wrote: > > > I've seen some talk about GFS on the list in the past. I'm > > currently looking at this as a potential solution to deploying > > Rails apps to 50+ servers. Basically to take advantage of GFS > > giving you a single disk/file-system across the servers; to help > > ensure truly one set of files deployed to all servers, faster > > deploys, etc. > > > > We currently have about 50+ servers, and that will grow. Our > > application architecture is SOA, so in reality one rails app won't > > be on all 50 servers, they'll be grouped, say 10-20 servers per > > service. > > > > I am currently eyeing a GFS setup where we use a server (per group) > > as a GFS disk, and GNBD across the machines. So, no SAN, no iSCSI, > > no fiber, etc. It's what I have available, so balancing the > > advantage of GFS vs. deploying the code to all machines in a more > > traditional setup. > > > > The servers in this case are 64bit boxes, with dual cores, and GigE > > (dual, but for this discussion assume a single one, since we split > > the net on them, etc.). Also, our application file storage is done > > using a different infrastructure, so it doesn't play into this. > > Databases are also on different boxes. > > > > I have not used GFS before, so I'm hoping for some input on some of > > these questions: > > > > - I presume that for the actual Rails application code, since it > > gets loaded up once in production mode, that say 20 servers pulling > > that from a single GNBD/GFS file system server would be no biggy. > > Correct? > > Yeah it's no biggy. > > > > > - Logs - this seems to be the danger area to me. Assuming we have > > "high traffic", and that we do quite a bit of logging (we log a > > lot of info for metrics and ability to follow requests through the > > SOA architecture, etc.), I worry about 20 servers all writing to a > > single log on the one GNBD/GFS server. Valid worry, or? Are there > > alternatives I should look at for logging in such an environment? > > > GFS has something called context dependant symlink. This lets you > make symlinks that resolve to a different path based on stuff like > hostname. So you setup a set of directories names after all the > hostnames in the cluster. THen make log a symlink to @hostname, observe: > > ey00-s00070 ~ # cd /data/ey/shared/ > ey00-s00070 shared # ls -lsa > total 32 > 4 drwxrwxr-x 7 ez ez 3864 Dec 3 2006 . > 4 drwxr-xr-x 4 ez ez 3864 Dec 7 15:14 .. > 4 drwxrwxrwx 2 ez ez 3864 Jun 1 13:30 ey00-s00070 > 4 drwxrwxrwx 2 ez ez 3864 Jun 4 22:07 ey00-s00071 > 4 lrwxrwxrwx 1 ez ez 9 Dec 3 2006 log -> @hostname > > > See how log is a symlink to @hostname? After you make a directory > namesd after all your hostnames that share a filesystem, you do this > to link them: > > $ ln -s @hostname log > > > > > - Thoughts, comments, notes on this approach in general? > > > > I have many many nodes running sharing GFS filesystems and it works > great in general, much more robust then NFS. I do it all off of a SAN > network though so I have no experience with the way you are trying to > do it with no san. > > > Cheers- > > -- Ezra Zygmuntowicz > -- Lead Rails Evangelist > -- [EMAIL PROTECTED] > -- Engine Yard, Serious Rails Hosting > -- (866) 518-YARD (9273) > > > > > > -- Chris Bailey [EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Deploying Rails" group. To post to this group, send email to rubyonrails-deployment@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/rubyonrails-deployment?hl=en -~----------~----~----~----~------~----~------~--~---
