Re: Cyrus/NFS/SMB
--On Monday, November 20, 2000 11:34:15 AM +1100 Tristan Ball <[EMAIL PROTECTED]> wrote: > Note: this is not something I have tried, or even wish to, as my largest > cyrus email server handles 250 users at the moment, easily handled by a > Sun E450. :-) > > I've seen the messages poo-pooing using NFS for cyrus, and the reasons > make sense, my question is would another shared filesystem, like > samba/smb/smbfs under linux be acceptable, or would I have I be better > off using a proper distributed filesystem like coda? Coda or AFS don't have the proper semantics for Cyrus, either. (Namely, both of them don't propogate changes to files until a close(), and Cyrus depends on changes to a file being immediately seen by other imap processes.) To make Cyrus work properly (and efficiently) with distributed filesystems, a good amount of work (and thought) needs to be done. MessagingDirect's IMAP server (based on Cyrus a long time ago) has done this work, and it's radically different from Cyrus at this point. Larry
Re: Cyrus/NFS/SMB
> My understanding is that Cyrus IMAPD itself is designed as a central > mailboxes (a special kind of files, in a way) server. Yes. > So it makes little sense to put the mailboxes themselves on a different The only place I think it might make sense is on cheap large scale servers. In particular, some of the NAS devices have their own advanced filesystems, (I forget which one I'm thinking of), which show much better performance for large numbers of small files than UFS normally does. So my architecture would be something like NAS box(es) backend, Multiple cheap linux boxes, plenty of memory/cpu, bugger all disk on the front end. It's only a theoritcal excersice anyway, in response to some of the other questions asked. There's also situations where you have a pure fileserver box, not a lot of memory but lots of disk, and you'd like to use a second machine with plenty of memory as the imap server... In reality, I'd be more likely to put together a cheapish linux box, with reiserfs and a couple of external raid boxes. I guess my real question was, does SMB suffer the same kind of remote locking issues that NFS does? It was probably better directed at the samba-tech mailing list. > (central) server. Having a NFS server re-exporting a SMB-mounted FS > is quite a nonsense... (unless you're really forced to do so, but be also > prepared to pay a price in performance and functionality). Think of IMAP Wouldn't dream of it. Actually I've done similar things in labs, but only for entertainment... NetBSD on a Mac LCIII, NFS to Linux box, NCP (netware) back out to a MacOS client. On 10mb shared hubs. Why? Because 75Kps is funny. :-) > just like another network file service. Building it on top of other one > is bad practice. Generally I agree. Simplicity is both astheticly pleasing, and easier to maintain. > See also: > http://asg.web.cmu.edu/cyrus/ag.html > (I can't find a way to reach this document from http://asg.web.cmu.edu/cyrus, > but there's a link in the doc directory of the source distribution). Yeah, I've seen it. One of these days I'll look at it too, but we really don't have a requirement for it. My userbase is spread thinly accross the planet, with several small-medium servers handling individual sites. I am intersted to see how well I can use the aggregator to give a unified IMAP namespace, particularly for shared folders, and especially accross (slow) WANS. I'd like my users in the UK to be able to see the same shared hierachies as the US ones, without showing them multiple servers. I don't think the current aggregator model suits that, it's really just a load balancer. -- -=*=-=*=--=*=-=*=-=*=- Tristan Ball System Administrator Vision Systems ph 03 9211 7064 -=*=-=*=--=*=-=*=-=*=-
Re: Cyrus/NFS/SMB
On Mon, 20 Nov 2000, Tristan Ball wrote: > Note: this is not something I have tried, or even wish to, as my largest > cyrus email server handles 250 users at the moment, easily handled by a > Sun E450. :-) > > I've seen the messages poo-pooing using NFS for cyrus, and the reasons > make sense, my question is would another shared filesystem, like > samba/smb/smbfs under linux be acceptable, or would I have I be better > off using a proper distributed filesystem like coda? > > Just curious. If you choose to respond, would you be so kind as to CC my > personal address, as I don't read this list as often as I would like. > > Thank you. > My understanding is that Cyrus IMAPD itself is designed as a central mailboxes (a special kind of files, in a way) server. So it makes little sense to put the mailboxes themselves on a different (central) server. Having a NFS server re-exporting a SMB-mounted FS is quite a nonsense... (unless you're really forced to do so, but be also prepared to pay a price in performance and functionality). Think of IMAP just like another network file service. Building it on top of other one is bad practice. See also: http://asg.web.cmu.edu/cyrus/ag.html (I can't find a way to reach this document from http://asg.web.cmu.edu/cyrus, but there's a link in the doc directory of the source distribution). .TM. -- / / / / / / Marco Colombo ___/ ___ / / Technical Manager / / / ESI s.r.l. _/ _/ _/ [EMAIL PROTECTED]
Cyrus/NFS/SMB
Note: this is not something I have tried, or even wish to, as my largest cyrus email server handles 250 users at the moment, easily handled by a Sun E450. :-) I've seen the messages poo-pooing using NFS for cyrus, and the reasons make sense, my question is would another shared filesystem, like samba/smb/smbfs under linux be acceptable, or would I have I be better off using a proper distributed filesystem like coda? Just curious. If you choose to respond, would you be so kind as to CC my personal address, as I don't read this list as often as I would like. Thank you. -- -=*=-=*=--=*=-=*=-=*=- Tristan Ball System Administrator Vision Systems -=*=-=*=--=*=-=*=-=*=-