Re: [OpenAFS] AFS and XEN Virtualization
On 7/9/07, Thomas Kula [EMAIL PROTECTED] wrote: AFS does not do read/write replicas. Why can't/doesn't it do this? Just curious. Zach ___ OpenAFS-info mailing list OpenAFS-info@openafs.org https://lists.openafs.org/mailman/listinfo/openafs-info
Re: [OpenAFS] AFS and XEN Virtualization
Zach wrote: On 7/9/07, Thomas Kula [EMAIL PROTECTED] wrote: AFS does not do read/write replicas. Why can't/doesn't it do this? Just curious. Several possible answers. (1) It's a _really_ hard problem (with surprisingly little payoff IMHO; better to put that effort into buying and maintaining reliable systems and networks). (2) It wasn't the interesting problem that AFS was designed to solve. The interesting problem AFS was designed to solve is, How do you support N clients accessing the same data when existing systems can only support M connections and N is much greater than M? AFS lets you replicate fairly static parts of your file name space across multiple servers so that you can (a) support more simultaneous clients than a single server could handle, and (b) have the beneficial side effect some degree of redundancy in the face of network flakiness. The fact that this latter feature compensates somewhat when the inaccessibility of a read-only server is be due to server trouble and not network instabilities is also just a fortunate side effect; it shouldn't be misconstrued as a High Availability design feature of the AFS server software. In other words, My servers are unreliable so I'd better run AFS on them isn't a plan for long term happiness. Other neat things that you get with it (single name space, a real authentication system, user manageable and useful ACLs, semi-transparent support for multiple architectures in the name space via the nifty @sys hack, etc.) are icing on the cake, but they fell out of the design process (I think; I wasn't there). The point of starting the design, however, was to answer the question of N clients on M-connection servers. Read/write replication was never on the table. -- +--+ / [EMAIL PROTECTED] 919-445-9302 http://www.unc.edu/~utoddl / / He is not only dull himself, he is the cause of / / dullness in others. - Samuel Johnson/ +--+ ___ OpenAFS-info mailing list OpenAFS-info@openafs.org https://lists.openafs.org/mailman/listinfo/openafs-info
Re: [OpenAFS] [vos] listvldb
So, no actual problem. I thought I remembered working on fixing something related to this with Kris Van Hees a while ago. On 7/10/07, Alessio Rocchi [EMAIL PROTECTED] wrote: I've got the version of OpenAFS that is installed on the machine where i ran the tests. It is a 1.2.13. I followed your advices and i moved to a new test-machine (the latest one got 1.4.0 installed). No more double string messages. Thank you, i was getting crazy about this problem. Sorry for letting you waste your time. Best regards, Alex
Re: [OpenAFS] [vos] listvldb
Derrick Brashear [EMAIL PROTECTED] had replied to Alessio Rocchi
Date:Tue, 10 Jul 2007 11:48:12 EDT
To: openafs-info@openafs.org
From:Derrick Brashear [EMAIL PROTECTED]
Subject: Re: [OpenAFS] [vos] listvldb
So, no actual problem. I thought I remembered working on fixing something
related to this with Kris Van Hees a while ago.
On 7/10/07, Alessio Rocchi [EMAIL PROTECTED] wrote:
I've got the version of OpenAFS that is installed on the machine where i
ran the tests.
It is a 1.2.13.
I followed your advices and i moved to a new test-machine (the latest one
got 1.4.0 installed).
No more double string messages.
Thank you, i was getting crazy about this problem.
Sorry for letting you waste your time.
Best regards,
Alex
Right, here's the code in 1.2.13 that does this:
~~~
if (isMixed) {
if (entry-serverFlags[i] NEW_REPSITE)
fprintf(STDOUT, -- New release);
else
if (!(entry-serverFlags[i] ITSRWVOL))
fprintf(STDOUT, -- Old release);
fprintf(STDOUT, -- Old release);
~~~
It's an edit gone bad - the final -- Old release message
always gets tacked on (and doesn't mean anything) if it just emitted
New or Old release.
Out of curiosity, is there any reason not to run 1.4.4 instead?
1.4.0 is not particularly recent...
-Marcus Watts
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