Re: HA with CentOS

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]



On Mon, 2007-05-14 at 13:08 -0400, Scott McClanahan wrote:
> On Mon, 2007-05-14 at 10:55 -0400, Ruslan Sivak wrote:
> > Steve Huff wrote:
> > >
> > > On May 14, 2007, at 10:25 AM, Ruslan Sivak wrote:
> > >
> > >> Steve Huff wrote:
> > >>
> > >> If you set up a third box to be the shared storage, doesn't that now 
> > >> become the single point of failure?
> > >
> > > Short answer: maybe. :)
> > >
> > > Longer answer: If you set up your shared storage according to 
> > > upstream's guidelines, as described in the documentation 
> > > (http://mirror.centos.org/centos/4/docs/html/rh-cs-en-4/ch-hardware.html#TB-HARDWARE-NOSPOF), 
> > > then you provide at least two channels of communication between each 
> > > component in the cluster.  In addition, you choose a platform for 
> > > shared storage that provides some redundancy of its own, whether it's 
> > > multi-controller HW RAID, or multiple storage nodes on a SAN, or what 
> > > have you.
> > >
> > > CS/GFS operates under the assumption that your shared storage is 
> > > fault-tolerant; its job is to make your services fault-tolerant.  Is 
> > > the recommended "no single point of failure" configuration proof 
> > > against your data center burning down, or against a madman with an 
> > > axe?  Unlikely.  Will it allow you to host services in a way that is 
> > > considerably more robust and flexible than hosting them on a single 
> > > box?  Yes.
> > >
> > > -Steve
> > >
> > 
> > I am currently running a redundant environment on windows by having 2 
> > boxes with apache and having the data (images) be synced over 
> > automatically between servers using FRS (File Replication Service).   
> > This works well most of the time, except for when it breaks, at which 
> > point I need to resync the two servers, which usually takes days. 
> > 
> > I would like to set up something similar using linux.  I don't have the 
> > budget for a SAN/NAS, and even having a third server as storage would 
> > probably not be worth it, although we can possibly go with this.  The 
> > problem, is that it would be a single point of failure. 
> > 
> > Is there some service/filesystem in Linux that allows for the automatic 
> > replication of files to make a fault tolerant environment possible with 
> > only 2 servers?  Basically whenever there is an update of a file on a 
> > certain file system (certain folder), the file gets synced over to 
> > another system. 
> > 
> > Russ

The is clustering include in CentOS-5 ... see the guides for using C5
Clustering here:

http://www.centos.org/docs/5/

> DRBD and Heartbeat seem pretty solid together for cheap affective high
> availability.  We've been using them for our production FTP servers
> which handle hundreds of thousands transactions a day both
> uploading/downloading.  We fail over between the two every 6 months and
> haven't had any problems on CentOS 4.3, they've actually been up for
> several hundred days now.  There is actually a yumgroup named
> drbd-heartbeat in the CentOS extras repository but I don't see that it
> is available in CentOS 5.0.  Does anyone know if these packages will be
> available in any of the CentOS 5.0 yum repositories?


There is a testing DRBD / Heartbeat for CentOS-5 in the testing repository:

http://dev.centos.org/centos/5/


Thanks,
Johnny Hughes

Attachment: signature.asc
Description: This is a digitally signed message part

_______________________________________________
CentOS mailing list
CentOS@xxxxxxxxxx
http://lists.centos.org/mailman/listinfo/centos

[Index of Archives]     [CentOS]     [CentOS Announce]     [CentOS Development]     [CentOS ARM Devel]     [CentOS Docs]     [CentOS Virtualization]     [Carrier Grade Linux]     [Linux Media]     [Asterisk]     [DCCP]     [Netdev]     [Xorg]     [Linux USB]
  Powered by Linux