> Hi. > > On 17.01.2017 19:09, Andy Dorman via Info-cyrus wrote: >> >> I am not an expert by any means and I hope someone corrects me if I >> make a bad suggestion...but I have two questions: >> >> 1. It sounds like you have a heavily used server, so why do you have >> Cyrus listening on both "localhost:lmtp" AND a unix socket >> "/var/imap/socket/lmtp"? >> >> From the log entry it looks like your MTA uses a unix socket. Unless >> you have something else (mail clients or other MTAs running on your >> Cyrus server?) that need to communicate via the localhost:lmtp port, >> you could comment out the unneeded lmtp service line and save those >> resources. > Well, on one hand you are right, seems like noone uses network lmtp > connections, but on the other hand how can the idle processes save > resources ? They only can save the memory, which doesn't seem to be the > problem. However, I will try you advice. >> >> 2. You say "increasing this value can make the situation even worse". >> Which value? There are 5 values on those two lines that you could >> increase. And by "even worse" do you mean even more refused >> connections? > The maxchild number. >> >> While I am not a Cyrus guru, I have seen my share of overloaded mail >> servers and if you are running into a disk IO limit, adding more >> processes fighting over a limited resource is very likely to make >> things worse. So you should also confirm a hardware limitation is not >> at play here. > Yup, this is exaclty what happens when increasing the maxchild number: > more messages start to bounce. And yes, the disks iops seems to be the > limiting factor. So, are there any other approaches besides scaling out > the disks iops ? I remember a situation more than a decade ago where we had to tune this. The problem with LMTP deliveries was that a lot of mails with hundreds of recipients on the same server were sent. Our Postfix MTA has sent every mail by a single LMTP transfer which resulted in high LMTP load and prevented effective usage of single instance store. The problem was solved by setting "local_destination_recipient_limit = X00" on the Postfix MTA (I don't remember the exact number). Regards, Simon ---- Cyrus Home Page: http://www.cyrusimap.org/ List Archives/Info: http://lists.andrew.cmu.edu/pipermail/info-cyrus/ To Unsubscribe: https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus
