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# remove any rd.lvm=0 occurrence | # remove any rd.lvm=0 occurrence | ||
# now start the modified grub entry | # now start the modified grub entry | ||
If all goes well, your system now boots fine and it's running on bcache! | If all goes well, your system now boots fine and it's running on LVM on bcache! Now we have to do some final housekeeping: | ||
# create a new /etc/grub2.cfg file: <code>grub2-mkconfig > /etc/grub2.cfg</code> | # create a new /etc/grub2.cfg file: <code>grub2-mkconfig > /etc/grub2.cfg</code> | ||
# rename your current initramfs (again): <code>mv /boot/initramfs...img /boot/initramfs...img.sav</code> | # rename your current initramfs (again): <code>mv /boot/initramfs...img /boot/initramfs...img.sav</code> | ||
# build a new initramfs with <i>only</i> the needed drivers included: <code>dracut</code> | # build a new initramfs with <i>only</i> the needed drivers included: <code>dracut</code> | ||
Now your system should be ready! | Now your system should be ready! | ||
# reboot your system to see if it boots OK. | # reboot your system to see if it boots OK | ||
# apply updates: <code>yum update</code>. Specifically try to update the kernel, because it depens on the proper interaction between dracut, bcache-tools and util-linux, | |||
# do some other testing if you like. | # do some other testing if you like. | ||
|results= | |results= | ||
# All steps complete without errors | # All steps complete without errors | ||
}} | }} | ||
Revision as of 12:49, 12 October 2013
Description
This page describes a test case for bcache-tools: "/ on bcache using LVM"
Bcache is a Linux kernel block layer cache. It allows one or more fast disk drives such as flash-based solid state drives (SSDs) to act as a cache for one or more slower hard disk drives. The bcache-tools package contains the utilities for manipulating bcache
Testing covers not only bcache-tools but also the interaction between bcache-tools and other packages: kernel, util-linux, dracut and lvm2.
Starting with a stable system with /home on LVM on bcache, we can go forward and have / on bcache. Consider thought that bcache is EXPERIMENTAL!
Prerequisites
This test requires the following test case as preparation: /home on bcache (LVM). Furthermore it requires the volume group BCACHE to have at least 2 GB free space!
Setup
If you haven't done so, you should first execute the use case /home on bcache (LVM).
How to test
To get / on bcache:
- create a Logical Volume:
lvcreate -L 2G -n ROOTFS BCACHE - create a filesystem:
mkfs -t ext4 -L ROOTFS /dev/BCACHE/ROOTFS - mount it:
mount /dev/BCACHE/ROOTFS /mnt - copy your current root filesystem to /mnt:
cp -ax / /mnt - edit /mnt/fstab so your root fs is mounted like:
LABEL=ROOTFS / ext4 defaults 1 1
Now we have a duplicate root filesystem on /dev/BCACHE/ROOTFS. To use it we need to build a new initramfs:
- rename your current initramfs:
mv /boot/initramfs...img /boot/initramfs...img.sav - build a new initramfs:
dracut -N
Now reboot your system.
- while booting edit the default grub entry and replace the root=UUID=... parameter in the "linux" line by: root=LABEL=ROOTFS
- remove any rd.lvm=0 occurrence
- now start the modified grub entry
If all goes well, your system now boots fine and it's running on LVM on bcache! Now we have to do some final housekeeping:
- create a new /etc/grub2.cfg file:
grub2-mkconfig > /etc/grub2.cfg - rename your current initramfs (again):
mv /boot/initramfs...img /boot/initramfs...img.sav - build a new initramfs with only the needed drivers included:
dracut
Now your system should be ready!
- reboot your system to see if it boots OK
- apply updates:
yum update. Specifically try to update the kernel, because it depens on the proper interaction between dracut, bcache-tools and util-linux, - do some other testing if you like.
Expected Results
- All steps complete without errors