dd would perhaps not be the end goal for any memory filesystem, but the major point is that when you remove files, tmpfs will (try to) return the memory to the OS, where mfs will not.
2014-05-06 8:28 GMT+02:00 Loïc Blot <loic.b...@unix-experience.fr>: > Hi @tech > i've migrated one of our squid server to OpenBSD 5.5 and i tested tmpfs. > It works like a charm, great work, but i noticed than the mfs is faster > than tmpfs. > > My benchs (with dd) are showing that tmpfs is slower than mfs. (/tmp: > tmpfs | /var/squid/cache: mfs), i've done many dd to test it, and i > always have the same results > > Writing performance > > dd if=/dev/zero of=/tmp/test.img bs=1024 > count=1000000 > 1000000+0 records in > 1000000+0 records out > 1024000000 bytes transferred in 8.706 secs (117614588 bytes/sec) > > dd if=/dev/zero of=/var/squid/cache/test.img bs=1024 count=1000000 > 1000000+0 records in > 1000000+0 records out > 1024000000 bytes transferred in 3.044 secs (336379694 bytes/sec) > > Reading performance > > dd if=/var/squid/cache/test.img of=/dev/null bs=1000 > 1024000+0 records in > 1024000+0 records out > 1024000000 bytes transferred in 2.767 secs (370015585 bytes/sec) > > dd if=/tmp/test.img of=/dev/null bs=1000 > 1024000+0 records in > 1024000+0 records out > 1024000000 bytes transferred in 3.553 secs (288178274 bytes/sec) > > Then, what is the goal of tmpfs ? Replace mfs ? Create a tmpfs structure > for some special dirs (like /dev, /tmp, /var/run...) ? If yes, is this > new tmpfs structure into fstab will be used in -current and next > release ? > > Thanks in advance > > -- > Best regards, > > Loïc BLOT, Engineering > UNIX Systems, Security and Network Engineer > http://www.unix-experience.fr > > > > -- May the most significant bit of your life be positive.
