I am not entirely familiar with Linux clustered filesystem. Maybe some one could point me in a direction for a real implementation for a disaster tolerant mailserver ?
As far as I understand the inode modification concept require applications to be linked in to new kernel code ? Some other file systems (like GFS) requires specific hardware as far as I understand (iSCSI or FC) and most of the Clustered file systems simply share the storage, usually SCSI and would sometimes be somewhat limited. My experience comes from OpenVMS clustering and If courier would be available on VMS it would have been my choice. But I may think that a VMS Cluster providing a NFS share, two or more Courier boxes that mount the NFS disk and a loadsharing device similar to LSNAT (RFC2391) and VRRP will do the job. The benefit with my concept would be that there are no kernel modifications and that the synchronisation may run over existing networks, and even slower lines that 10 Mbps, depending on application load. /Lars ----- Original Message ----- From: "Mitch (WebCob)" <[EMAIL PROTECTED]> To: "Lars Holmstr�m" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Monday, July 14, 2003 8:03 PM Subject: RE: [courier-users] Disaster tolerant IMAP and SMTP ? Hmmm... Interesting concept, but I wonder what performance gain it would provide - something like rsync uses inode mtimes to only traverse file system points that have been changed - pretty efficient, and it doesn't restrict itself to a single application. I wonder what the overhead and sequencing of access to such a change log would be compared with the existing methods... Interesting thought though. m/ > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Lars > Holmstr�m > Sent: July 14, 2003 8:14 AM > To: [EMAIL PROTECTED] > Subject: Re: [courier-users] Disaster tolerant IMAP and SMTP ? > > > Some one pointed out that this an off-topic problem. I did some research and > got some feedback from this list and will probably build an example of a > redundant system, and this will be based on a clustered multi site file > system. > > However, I see another possible solution where courier IMAP server may have > a transaction log implemented and then one or more mailservers may > synchronize based on this log. For example, when some one logs out from the > IMAP server, the server may syncronize with the neighbours. Or by setting > synchronize_level=high one may establish a connection between all neighbours > as soon as you got a login, and then synchronize instantly. > > Maybe this is not within the scope of the courier application, but still > people may have to solve the problem and as far as I understand there are no > good solutions around ? > > /Lars > > > ----- Original Message ----- > From: "Systems Administrator" <[EMAIL PROTECTED]> > To: "Lars Holmstr�m" <[EMAIL PROTECTED]> > Cc: <[EMAIL PROTECTED]> > Sent: Monday, July 14, 2003 2:40 AM > Subject: Re: [courier-users] Disaster tolerant IMAP and SMTP ? > > > On Sat, 12 Jul 2003, Lars Holmstr�m wrote: > > > I consider building a disaster tolerant mailsystem for in and outgoing > mail. > > > > I already have two ISPs and MX records that direct incoming mailtraffic > properly. > > > > The problem seems to be the IMAP. > > > > Does any one have a suggestion for how to do this ? > > > > /Lars > > Ps. Disaster tolerant in my view is when I can afford to loose one > computerroom completely and the service from a users perspective is still > available. Ds. > > I've looked all around, but seen nothing that seems to be a > complete solution. I've documented what I've found at: > > http://www.defendmail.sunet.com.au/Projects/RedundantMail/ > > I've also got a mailing connected with this page, and have been > hoping to get some people together to discuss it, but currently I think > its just me on the mailing list. > > :) > > -- > Tim Nelson > Systems Administrator > Sunet Internet > Tel: +61 3 5241 1155 > Fax: +61 3 5241 6187 > Web: http://www.sunet.com.au/ > Email: [EMAIL PROTECTED] > > > > > > > ------------------------------------------------------- > This SF.Net email sponsored by: Parasoft > Error proof Web apps, automate testing & more. > Download & eval WebKing and get a free book. > www.parasoft.com/bulletproofapps1 > _______________________________________________ > courier-users mailing list > [EMAIL PROTECTED] > Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users > ------------------------------------------------------- This SF.Net email sponsored by: Parasoft Error proof Web apps, automate testing & more. Download & eval WebKing and get a free book. www.parasoft.com/bulletproofapps1 _______________________________________________ courier-users mailing list [EMAIL PROTECTED] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
