Hi all I would also be interested in hearing about anyone using SAN technologies especially iSCSI to provide storage to a sendmail/IMAP server?
I like to idea of being able to move the storage off the server to improve reliability. We could move the service (and data) between servers with just a few commands, useful when a server fails. Software updates could be installed and tested during the week on a backup server with only a small brake in service when they are put into production, should reduce the amount of weekend and out of hours working. >From comments on the list I/O seems to be critical performance factor, I don't know if iSCSI would cause problems with this. My setup is probably quite small, with several hundred user but less than 100 actually connected at anyone time and the total disk space for email is about 45Gbyte. We have a small number of users who don't use folders and keep everything in their inbox. As a result some of the inboxes contain thousands of messages and range in size from a few hundred Mbyte to over a Gbyte, opening these takes some time and puts a load on the server. For anyone new to iSCSI here is a short description iSCSI is a Storage Area Network rather then a network file system, think of a Fibre Channel SAN but using IP and Gigabit Ethernet to deliver the block level access rather than Fibre Channel. http://whatis.techtarget.com/definition/0,,sid9_gci750136,00.html or a google search http://www.google.com/search?hl=en&q=iscsi&btnG=Google+Search To the host it looks like any other SCSI disk which you create a standard file system on. Partitions or LUNs are not usually accessed by more then one host between unless you are using a special file system. By centralising the storage away from the server you gain economies of scale and manageability. Also if a server fails it's easy and very quick to remount the partition on a different server and resume service. There is no need to move disks or cables between servers, you might need to update the SAN access rules to allow the new server to see the disk. Backup can be easer if your storage array also includes features such as snapshots. Richard Westlake School of Crystallography, Birkbeck College, Malet Street, London WC1E 7HX Tel: 020-7631-6859 ---------------------------------------------------------------------- Truth endures but spelling changes -- Anon. ---------------------------------------------------------------------- On Tue, 23 Nov 2004, Yiorgos Adamopoulos wrote: > Date: Tue, 23 Nov 2004 13:39:09 +0200 > From: Yiorgos Adamopoulos <[EMAIL PROTECTED]> > To: [EMAIL PROTECTED] > Subject: MBX mailboxes over iSCSI > > Does anybody have any experiense on such a configuration? iSCSI > partitions look like local disks to the OS (or at least this is my > understandig) but in truth they reside on another server on the network. > > I am going to have 20K mailboxes, but by 2005/06 I may be forced to > increase this number to an order of magnitude (nearing 100K) > -- > ------------------------------------------------------------------ > For information about this mailing list, and its archives, see: > http://www.washington.edu/imap/c-client-list.html > ------------------------------------------------------------------ >
