dovecot: imap(root@localhost)<3702>: Error: Mailbox INBOX: mmap(size=352609044) failed with file /var/spool/mail/root/Maildir/dovecot.index.cache: Cannot allocate memory
If you get this error you may assume it is a lack of memory, which it could be, but more likely it is the default memory size of 256M. The file in this example was about 350M big which of course exceeds the virtual memory limits.
This makes sense in smaller mail servers but if you have large amounts of users or e-mails this limit should be bumped.
Check your default size limit:
doveconf -n | grep -E 'vsz_limit|service imap'
default_vsz_limi........
How to change reserved blocks in Linux partition
user@box:~$ sudo tune2fs -l /dev/md99
[sudo] password for user:
tune2fs 1.42.9 (4-Feb-2014)
Filesystem volume name:
Last mounted on: /mnt/md50
Filesystem UUID: 976a8655-2619-4587-878c-dab07f7b7652
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Fi........
Linux EXT3 16GB-17GB maximum filesize issue solved/how to fix
I have no idea why but mkfs.ext3 defaults to a patheticlly small blocksize of 1024 bytes/1KB (kilobyte). That means the maximum filesize is ONLY 16GB! With 2KB/2048 bytes you get a 256 GB maximum filesize, and with 4KB/4096 bytes you get 2TB!
I finally noticed/paid attention to this after realizing that with rsync and scp that no file larger than 17GB could be transferred. I then realized it must be a file size limit on the partition.
Here is what tune2fs tol........