Testing #zswap in #Fedora 19
Dietrich Schmitz would be interested in this...
One of the new features of the 3.11 Linux kernel was the zswap driver. When there is a need to start swapping zswap wil first try compressing data in memory. This will load the CPU with some compression/decompression, but will avoid slow writes to disk.
If you want to start testing zswap right now, these are the steps required:
First, install the required kernel. If Fedora still doesn't have a 3.11 or later kernel in the standard repo, try running
yum --enablerepo=\*testing\* update \*kernel\*
If this offers a 3.11 or later kernel you are set. if not, try installing the repo file for rawhide:
yum install fedora-release-rawhide
and then add the 3.12 or later from there:
yum --enablerepo=\*rawhide\* update \*kernel\*
Rawhide is more or less the alpha version of what will become Fedora.
Edit /etc/sysconfig/grub and add zswap.enabled=1 to the end of the GRUB_CMDLINE_LINUX line. then run
grub2-mkconfig -o /boot/grub2/grub.cfg
and reboot.
dmesg | grep zswap
will show some output if installation was successfull.
Leave a comment with your impression of zswap,
this will work for 20 also?
SvarSletti think a 3.11 or greater kernel is now standard in both 19 and 20, so no need for the yum commands anymore.
SvarSlettJust fix your grub.conf and reboot.
Sure does work on Fedora 20, thanks for this!
SvarSlettI have tried this countless times on Fedora 20 and 21, and I absolutely cannot get it to work under any circumstances. It works when I directly edit the kernel boot line in grub, but it seems impossible to make the change persistent. Shame, because it seems like a cool idea.
SvarSlettI get the following upon reboot and dmesg:
SvarSlett$ dmesg | grep zswap
[ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.17.2-200.fc20.x86_64 root=UUID=ba83bf89-67ff-47ec-9931-0ea074340d38 ro rd.md=0 rd.lvm=0 rd.dm=0 vconsole.keymap=us rd.luks=0 vconsole.font=latarcyrheb-sun16 resume=UUID=2f4e50c0-ec62-4318-ade2-3413cbcb1c35 zswap.enabled=1
[ 0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-3.17.2-200.fc20.x86_64 root=UUID=ba83bf89-67ff-47ec-9931-0ea074340d38 ro rd.md=0 rd.lvm=0 rd.dm=0 vconsole.keymap=us rd.luks=0 vconsole.font=latarcyrheb-sun16 resume=UUID=2f4e50c0-ec62-4318-ade2-3413cbcb1c35 zswap.enabled=1
[ 0.741268] zswap: loading zswap
[ 0.743636] zswap: zbud zpool not available
[ 0.743757] zswap: zpool creation failed
What is this zbud zpool not available message? I DDG'ed but nothing of value came up. Any suggestions?
for me is working fine
SvarSlett[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-3.11.1-300.fc21.x86_64 root=UUID=fc2bdcf8-db97-45e0-aa37-9e917178eece ro rhgb quiet zswap.enabled=1
[ 0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.11.1-300.fc21.x86_64 root=UUID=fc2bdcf8-db97-45e0-aa37-9e917178eece ro rhgb quiet zswap.enabled=1
[ 2.055826] zswap: loading zswap
[ 2.055831] zswap: using lzo compressor