>> This may not be exactly a Postfix question, but related...
>> I have noticed that when there are a lot of emails in the deferred queue and
>> i use 'postqueue -f' to send them all, vmware virtual servers
>>
>> are incredible much faster than physical servers!!
>
>
>You say both servers run off SSD and have plenty memory. Remaining
>differences:
>
>- Your VMM cheats, by disabling SYNCHRONOUS UPDATES of the virtual
>disk. This means you lose mail when the host OS crashes. Postfix
>requires that fsync returns after the data is stored. With caching
>in host memory, fsync returns while the data sits in host memory.
>
>- Your OS in the VM has atime updates disabled, and the physicsal
>host not.
>
>Or a combination of the above.
- Makes total sense that fsync falsely returns before all data are written to
real drive in a VM... i did not know Postfix waits for fsync, thanks Wietse!
- Regarding atime... is qmgr 'atime' dependant? or maybe you suggest it due to
the time the OS takes to update the 'atime'?
What i have noticed, Wietse, is that inmediatelly after the "postqueue -f" the
log shows tons of qmgr messages like this:
postfix/qmgr[65371]: ED9FD4209E4: from=<>, size=22211, nrcpt=1 (queue
active)
And then..
- Immediately many successful postfix/smtp lines... (in the VM)
- After a long delay many successful postfix/smtp lines... (in the Physical
server)
May this delay be due to the qmgr files movement from deferred to active
folders? that would be coherent with the fsync issue... since it only affects
writes to disk, not reads.
Thanks Wietse!
Pete.
