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) --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
