Sizing an IMAP Server on OpenBSD
Hi everyone, I'm planning to deploy a SMTP(Sendmail) and IMAP(Cyrus) server on a mid-sized organization(~300 remote users, dunno about messages/day), and since is my first IMAP server (until now we do only POP), I have some questions about sizing. First, about hardware requirements. I had tought to use a Dell 1850, 2GB RAM with two controllers: a PERC4e/Si for system + sendmail queue, and a PERC 4e/DC connected to a PV220s, with 7x300GB (half of backplane) for imap data (4 or 6 discs in RAID-10 + 1 hot spare) . I think it should be enough, but it's really? (the hardware it's already bought, so I really hope so). Any recommendations about stripe size or raid configuration?, which ami version to use? -stable one? How ami's performance compares with FreeBSD's amr? I understand that is advisable to run softupdates on the imap and /var/spool partitions, and to disable fsck on boot, but what about increasing buffer cache size? 5% of physical memory seems a bit low for an I/O intensive app as Cyrus is. About resource limits of _cyrus user and sysctl values, are there well known values? Should I increase kern.maxfiles for example? I wouldn't like to learn it at production time. Well, this are my questions. May be the hardware is overkill for our load, but sizing hardware without prior experience it's always a difficult task, so if anybody wants to share their experience... Thanks in advance, Samuel
Re: Sizing an IMAP Server on OpenBSD
IF you're only talking about around 300 users, you've probably not got to worry about these questions - what you have will work very well for what you are proposing, likely without any tweaks. -Bob * Samuel Moqux [EMAIL PROTECTED] [2006-07-07 10:56]: Hi everyone, I'm planning to deploy a SMTP(Sendmail) and IMAP(Cyrus) server on a mid-sized organization(~300 remote users, dunno about messages/day), and since is my first IMAP server (until now we do only POP), I have some questions about sizing. First, about hardware requirements. I had tought to use a Dell 1850, 2GB RAM with two controllers: a PERC4e/Si for system + sendmail queue, and a PERC 4e/DC connected to a PV220s, with 7x300GB (half of backplane) for imap data (4 or 6 discs in RAID-10 + 1 hot spare) . I think it should be enough, but it's really? (the hardware it's already bought, so I really hope so). Any recommendations about stripe size or raid configuration?, which ami version to use? -stable one? How ami's performance compares with FreeBSD's amr? I understand that is advisable to run softupdates on the imap and /var/spool partitions, and to disable fsck on boot, but what about increasing buffer cache size? 5% of physical memory seems a bit low for an I/O intensive app as Cyrus is. About resource limits of _cyrus user and sysctl values, are there well known values? Should I increase kern.maxfiles for example? I wouldn't like to learn it at production time. Well, this are my questions. May be the hardware is overkill for our load, but sizing hardware without prior experience it's always a difficult task, so if anybody wants to share their experience... Thanks in advance, Samuel -- | | | The ASCII Fork Campaign \|/ against gratuitous use of threads. |
Re: Sizing an IMAP Server on OpenBSD
thus Bob Beck spake: IF you're only talking about around 300 users, you've probably not got to worry about these questions - what you have will work very well for what you are proposing, likely without any tweaks. -Bob * Samuel Moqux [EMAIL PROTECTED] [2006-07-07 10:56]: Hi everyone, I'm planning to deploy a SMTP(Sendmail) and IMAP(Cyrus) server on a mid-sized organization(~300 remote users, dunno about messages/day), and since is my first IMAP server (until now we do only POP), I have some questions about sizing. First, about hardware requirements. I had tought to use a Dell 1850, 2GB RAM with two controllers: a PERC4e/Si for system + sendmail queue, and a PERC 4e/DC connected to a PV220s, with 7x300GB (half of backplane) for imap data (4 or 6 discs in RAID-10 + 1 hot spare) . I think it should be enough, but it's really? (the hardware it's already bought, so I really hope so). Any recommendations about stripe size or raid configuration?, which ami version to use? -stable one? How ami's performance compares with FreeBSD's amr? I understand that is advisable to run softupdates on the imap and /var/spool partitions, and to disable fsck on boot, but what about increasing buffer cache size? 5% of physical memory seems a bit low for an I/O intensive app as Cyrus is. About resource limits of _cyrus user and sysctl values, are there well known values? Should I increase kern.maxfiles for example? I wouldn't like to learn it at production time. Well, this are my questions. May be the hardware is overkill for our load, but sizing hardware without prior experience it's always a difficult task, so if anybody wants to share their experience... Thanks in advance, Samuel hm, two years ago i had to migrate a 20 user advertising company (not very small mails ;) from 'exchange' to cyrus. because of weird circumstances, i had to use a temporary setup for about two months. this was an Amiga 1200 with 68040 turbo board, external SCSI HD, and 256MByte RAM running Cyrus 2.2.x, Postfix 2.x, clamav and amavisd-new on NetBSD. that's a really true story :) without amavisd-new, even less memory would have been sufficient ;) timo
Re: Sizing an IMAP Server on OpenBSD
First, about hardware requirements. What you're proposing is absolute overkill for such a small client load. You won't need to upgrade the hardware :-) About resource limits of _cyrus user and sysctl values, are there well known values? Should I increase kern.maxfiles for example? I wouldn't like to learn it at production time. Again, given the minimal load from IMAP, the out of the box defaults will do just fine. Well, this are my questions. May be the hardware is overkill for our load, but sizing hardware without prior experience it's always a difficult task, so if anybody wants to share their experience... Cyrus has a very small CPU and memory footprint. All you need to ensure is that you have enough I/O bandwidth from the disk, through the imapd process, and out the network interface. From what you're describing, you have nothing to worry about. Sendmail can want memory when delivering messages with large numbers of recipients (e.g. mailing list expansion), but again, it's doubtful your load will even begin to stress the hardware. --lyndon
