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Arthur Sherman wrote:
>> Applications that are /dev/shm-aware usually take care of it
>> automagically,
>> there's nothing to configure. However, you can get better
>> performance out
>> of some applications by also mounting /tmp as a tmpfs filesystem.
>>
>
> However, MailScanner, which appears to be shm-aware, wasn't so as a default.
> I had to mount it to shm:
>
> [root@ns1 ~]# df -h
> Filesystem Size Used Avail Use% Mounted on
> /dev/md1 6.0G 1.1G 4.6G 20% /
> /dev/md6 99M 12M 83M 12% /boot
> none 1.5G 0 1.5G 0% /dev/shm
> /dev/md4 135G 2.5G 126G 2% /home
> /dev/md2 1012M 40M 921M 5% /tmp
> /dev/md3 4.0G 302M 3.5G 8% /var
> none 1.5G 32K 1.5G 1% /var/spool/MailScanner/incoming
> [root@ns1 ~]# cat /etc/fstab
> # This file is edited by fstab-sync - see 'man fstab-sync' for details
> /dev/md1 / ext3 defaults 1 1
> /dev/md6 /boot ext3 defaults 1 2
> none /dev/pts devpts gid=5,mode=620 0 0
> none /dev/shm tmpfs noexec,nosuid,rw
> 0 0
> /dev/md4 /home ext3
> defaults,usrquota,grpquota 1 2
> none /proc proc defaults 0 0
> none /sys sysfs defaults 0 0
> /dev/md2 /tmp ext3 defaults 1 2
> /dev/md3 /var ext3 defaults 1 2
> /dev/md5 swap swap defaults 0 0
> # this is from MailScanner.info MAQ:
> http://www.mailscanner.info/serve/cache/120.html
> none /var/spool/MailScanner/incoming tmpfs defaults 0 0
> /dev/hdb /media/cdrom auto
> pamconsole,exec,noauto,managed 0 0
>
> BTW, it appears I was hasty to say I have /tmp mounted as tmpfs.
> Now, I recall someone told me off, arguing it will break things, such as yum
> etc.
>
If yum is broken by /tmp being a tmpfs then it is truly a worse
application then I ever imaged it is...
In reality, no application should break since a tmpfs is just a fake
filesystem which never writes anything to disk.
Common configurations are similiar to:
none /dev/shm tmpfs
nodev,nosuid,noexec 0 0
none /tmp tmpfs
noatime,size=128M 0 0
Sometimes you will see /tmp implemented as:
none /tmp tmpfs
noatime,nosuid,nodev,size=128M 0 0
But it's all a security thing at that point.
> How serious is it?
> I'd really like to make as much apps work from tmpfs as possible, for
> obvious performance advantage
>
>
> Best,
>
> --
> Arthur Sherman
>
> +972-52-4878851
> http://www.cpt.co.il/
>
>
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