[ale] OCFS2

[Jeff Hubbs]

I perhaps should have followed the situation more closely in the past 
couple-odd years, but you're alluding to a level of fault tolerance 
that's not easy to hit, at least not at Free Software prices.

Both the operating system and the app have to be able to cooperate with 
such a scheme - that's where the trouble comes in.  In c. 2000, 
TurboLinux' own clustering white papers proposed using Oracle on Solaris 
for such.  MS SQL Server on the appropriate "edition" of Win2K5 is 
probably another option; IIRC, it uses a main/auxiliary model for 
service failover.  I doubt if either scheme will operate without some 
sort of burp on failover, even if all that's felt is a delay. 

Having more than one OS instance access the same disks at once is one of 
the things that VMS had game on 20 years ago, and it's still available 
although running it in practice seems to be like threading a needle with 
an ever-shrinking eye.

Christopher Fowler wrote:

>On Mon, 2006-03-20 at 11:46 -0500, Chris Ricker wrote:
>  
>
>>On Mon, 20 Mar 2006, Christopher Fowler wrote:
>>
>>    
>>
>>>http://lwn.net/Articles/137278/
>>>
>>>Could I use OCFS2 to cluster 2+ servers that are running MySQL so if one
>>>goes down the other could simply jump in its place?
>>>
>>>What I like about this idea is that instead of using a central RAID
>>>cabinet that could die both boxes could simple share the same /opt/RUN
>>>file system.  The backups could simply have mysql turned off an then a
>>>script could turn it on.  
>>>      
>>>
>>You should be able to. Note that OCFS2, unless things have changed, 
>>requires physically shared storage - two hosts sharing the same LUNs from 
>>a SAN or similar
>>
>>    
>>
>
>Oh.  I guess I was looking more of where 2 servers do RAID1 together.
>
>server1:/dev/sda2 and server2:/dev/sda2 are mirrored so that either one
>could have access to the files in case the other dies.
>
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