IMAP Quota Support
Amidst the massive confusion users experience when they suddenly find themselves over quota with little notification aside from within the control panel, I’ve patched Dovecot’s quota reporting extension to work correctly with the servers. Even better, it’s reported in SquirrelMail and Horde now too. In summary, the quota reporting works like this: check if there’s a user quota limit and it’s less than the account quota limit; if so, report that, otherwise report the total account quota used and account quota limit.
Postfix 2.5 will be rolled out on the servers tonight with another very important enhancement designed to protect against accounts monopolizing the mail server. Delays may be configured between delivery attempts in order to prohibit one particular e-mail account from consuming all delivery slots as we saw earlier this week. Currently Postfix will add a 10 second delay between delivery attempts to the same address. For example, let’s say you’ve been inundated with a spam flood of 100 messages destined to your e-mail account all of which were accepted on the mail server’s end in a 2 second window. Postfix 2.4 and earlier would attempt to deliver all of the messages at once, quickly tying up delivery slots in the process as each message is scanned by SpamAssassin and hopelessly delivered. Another new feature in Postfix 2.5 is the revised scheduling algorithm that takes into account feedback to determine if a hop is up or down.
I’ve heard 2 reports from users experiencing authentication difficulties with the new vsFTPd+ build. I have been unable to confirm the bug from my end. I am waiting on a packet trace from another customer with Ethereal later on tonight. If I can get that squared away, then vsFTPd+ will be rolled out on the servers tonight otherwise we’ll hold off until that bug is understood.
sky2 NIC Drivers
Despite having extremely high hopes that the 2.6.24 Linux kernel would address the deadlocking problems present in Marvell Yukon XL chips, it’s still an off and on problem. Issues have been further exacerbated by an unexpected kernel panic on Assmule Wednesday night. No other servers have exhibited a kernel panic, but we’re still seeing the NIC lose connectivity for 10-15 seconds randomly. Fortunately it is extremely rare; Augend has had it happen once this week and 10 seconds/604800 seconds is such a marginal number you could chock it up to random network glitches elsewhere. Anyway, I am still following the threads as they pop up on the LKML and I’ll let you know if anything turns up.
Because we are destined for another kernel upgrade in the next few months it’s a good time to think about adding rc.local support to each user’s Basic and higher account. rc.local allows you to include commands that are executed upon boot by the server. There’s a global rc.local we use to set readahead rates on the hard drives and toss up any auxiliary services, but as I know from process output, many individuals run their own services like mongrel, pen, svnserve, and the like, which are critical to your site. You can’t always be around when there’s a kernel panic like with Assmule and often times you won’t witness it. Servers can recover in as little as 3 minutes. That is less time than it takes to go to the bathroom and come back if you’re gifted in the large bladder department. rc.local will be rolled out next week.
That’s all for this Friday’s installment. Log rotation support in the control panel will be split between a basic and advanced editor… in case you were curious as to the hold-up.