Re: [Dovecot] Redundant shared mail store?
Jasper Bryant-Greene wrote:
Hi guys
I'm about to embark on a project replacing a legacy single mail server running proprietary software with a cluster of Dovecot servers. We clearly need a shared mail store for these servers, but we are not happy with simply using a server running NFS as this becomes a single point of failure.
What have other people used? AFAICT our options are:
A shared block device (Fibre Channel, iSCSI, ATAoE etc) running GFS or similar to allow multiple servers to access it concurrently
Two or more NFS units, either with built-in support for replication of FS changes and failover, or with scripts for achieving this functionality
I prefer option 1, although it's expensive. What have other people used? Do we have other options?
I recommend a pair of NetApp filers (e.g. 2 x 3020c) exporting NFS from shared disk shelves in their high-availability mode. This is a hybrid of the two options, except a) it's a fully supported and stable NetApp configuration, b) they're sharing disk storage, c) you're not hog-tied to GFS, d) it's the best NFS implementation in the world (you can even trust the fcntl locking), e) it's really fast, f) NetApp's onboard snapshots and other funky software bits will make you wonder how you lived without them, g) the HA actually works.
I have a six-digit userbase with mailboxes in this configuration.
JG
Joshua Goodall wrote:
Hi guys
I'm about to embark on a project replacing a legacy single mail server running proprietary software with a cluster of Dovecot servers. We clearly need a shared mail store for these servers, but we are not happy with simply using a server running NFS as this becomes a single point of failure. [snip] I recommend a pair of NetApp filers (e.g. 2 x 3020c) exporting NFS from shared disk shelves in their high-availability mode. This is a hybrid of the two options, except a) it's a fully supported and stable NetApp configuration, b) they're sharing disk storage, c) you're not hog-tied to GFS, d) it's the best NFS implementation in the world (you can even
Jasper Bryant-Greene wrote: trust the fcntl locking), e) it's really fast, f) NetApp's onboard snapshots and other funky software bits will make you wonder how you lived without them, g) the HA actually works.
I have a six-digit userbase with mailboxes in this configuration.
Thanks for replying - our budget won't stretch to that sort of device, and it's possibly overkill in terms of storage capability (our mail currently fits in 100GB easily) but we do like the redundancy/HA features.
Are there any options with similar redundancy/high-availability capabilities but more in the mid-range market?
-- Jasper Bryant-Greene Director Album Limited
jasper@albumltd.co.nz +64 21 708 334 / 0800 425 286 http://www.albumltd.co.nz/
Joshua Goodall wrote:
I recommend a pair of NetApp filers (e.g. 2 x 3020c) exporting NFS from shared disk shelves in their high-availability mode. This is a hybrid of the two options, except a) it's a fully supported and stable NetApp configuration, b) they're sharing disk storage, c) you're not hog-tied to GFS, d) it's the best NFS implementation in the world (you can even trust the fcntl locking), e) it's really fast, f) NetApp's onboard snapshots and other funky software bits will make you wonder how you lived without them, g) the HA actually works.
I have a six-digit userbase with mailboxes in this configuration.
Hi,
My ears prick up whenever I hear mention of NetApps and Dovecot.
Which operating system (Linux, Solaris, Solaris x86...) are you running.
Many thanks, Jonathan.
On 10/30/06, Joshua Goodall joshua_goodall@pacific.net.au wrote:
...
I recommend a pair of NetApp filers (e.g. 2 x 3020c) exporting NFS from
shared disk shelves in their high-availability mode. This is a hybrid of the two options, except a) it's a fully supported and stable NetApp configuration, b) they're sharing disk storage, c) you're not hog-tied to GFS, d) it's the best NFS implementation in the world (you can even trust the fcntl locking), e) it's really fast, f) NetApp's onboard snapshots and other funky software bits will make you wonder how you lived without them, g) the HA actually works.
I have a six-digit userbase with mailboxes in this configuration.
JG
We are in the process of rolling out / migrating mail from various "other" imap stores to a cluster of two servers running dovecot-1.0.beta9 attached to a 3050c cluster. Hosts are running RHEL4u3 on x86_64 on the latest official kernel, 2.6.9-42.0.3.ELsmp. NFS mount options on both machines are (rw,nosuid,nodev,tcp,nfsvers=3,rsize=8192,wsize=8192,soft,intr,noac,actimeo=0). We are using default_mail_env with Maildir/indices stored over NFS. Postfix with procmail delivery. Currently we are using DNS round robin as there is no SLB in the mix just yet. It is extremely fast.
The only thing I am still mildly concerned about are some errors regarding index corruption. These are seen on both machines. Hopefully a newer version fixes these. See below:
dovecot: Oct 31 11:56:52 Error: IMAP(user): Corrupted index cache file mailstore/user/Maildir/.My-Folder.blah/dovecot.index.cache: invalid record size
These errors don't appear to have any impact on the client side, performance or otherwise.
participants (4)
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bofh list
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Jasper Bryant-Greene
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Jonathan
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Joshua Goodall