[Linux-cluster] Re: Linux-cluster Digest, Vol 20, Issue 14

[Alan Wood]

you can look at my post from Nov 15 of 2004 to see the effects I 
experienced running samba on top of GFS.  whether or not the problems stem 
purely from locking I don't know (I played extensively with the locking 
options in my smb.conf, to no avail), but the crashes [and delays] I saw 
when I had multiple users access the same file/share made the system 
unusable in production. 
whenever I've pushed on this question people seem to fall into one of two 
camps:
1.  never tried running samba on top of GFS with high load, but thinks it 
should work
2.  acknowledges there might be some underlying problems

if there is a 3rd camp out there of people who are running samba sharing on 
top of GFS I'd love to hear about it.  My experience says it'll start up 
fine and probably work ok under light load (say, 5 users) or if users only 
ever access their own shares.  but as soon as you have multiple users 
accessing a common samba share you start experiencing [unacceptable] delays 
and if something else is going on (say a webserver serving the same path) 
you'll probably get a crash.
-alan

On Tue, 13 Dec 2005 linux-cluster-request at redhat.com wrote:

> Date: Tue, 13 Dec 2005 09:26:38 -0600
> From: Eric Anderson <anderson at centtech.com>
> Subject: Re: [Linux-cluster] Re: Linux-cluster Digest, Vol 20, Issue
> 	12
> To: linux clustering <linux-cluster at redhat.com>
> Message-ID: <439EE82E.2080106 at centtech.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Marco Masotti wrote:
>
>>> ==========================
>>> Date: Tue, 13 Dec 2005 01:42:11 -0800 (PST)
>>> From: Alan Wood <chekov at ucla.edu>
>>> To: linux-cluster at redhat.com
>>> Subject: [Linux-cluster] Re: Linux-cluster Digest, Vol 20, Issue
>>> 12
>>> ==========================
>>>
>>>
>>
>>
>> [...]
>>
>>
>>
>>> SMB is stateful and not cluster
>>> aware,
>>>
>>>
>>
>>
>> I'm defintely missing something in my assumptions. By its very nature, 
>> shouldn't GFS be prescinding from its application, as in every other 
>> filesystem?
>>
>> Also, pls allow the ingenuous question, what number of applications 
>> needs ever to be cluster aware, if not a very strict one? Also, 
>> intuitively as it may come, should a properly written applicative be 
>> independent of the operating filesystem properties? Thanks.
>>
>>
>
> I agree here - GFS supposedly supports posix semantics, so the
> application should not care about whether it is clustered or not, as
> long as it using locking correctly on it's own.  At least, with other
> clustered filesystems, this is the case. If GFS doesn't allow this, I
> would say it isn't really a cluster aware filesystem, but more of a
> distributed lock/cache coherent filesystem without fully clustered
> semantics.. (please correct me here! I'm still learning)
>
> Eric
>
>
>
>
>