Boot scripts for write-thru and write-around cache creation

[Shahar Or]

Three types of caches are supported in flashcache: Write-back, write-thru and write-around.

Write-back type caches require launching of 'flashcache_load' on before they can be mounted.

For write-back type caches there's a udev rule in the packaging that does this automagically so you can add your flashcache write-back type cache(s) to fstab and they will be mounted at boot up.

Write-thru and -around cache devices need to be created with 'flashcache_create' after each boot.

My request is for boot scripts that will create write-thru and write-around cache devices on boot up and a configuration file to go along with that.

Thank you,
Shahar

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: flashcache-utils 1.0+git20121114-1
ProcVersionSignature: Ubuntu 3.8.0-15.25-generic 3.8.4
Uname: Linux 3.8.0-15-generic x86_64
ApportVersion: 2.9.2-0ubuntu5
Architecture: amd64
Date: Sun Mar 31 10:40:28 2013
EcryptfsInUse: Yes
InstallationDate: Installed on 2010-10-12 (900 days ago)
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
MarkForUpload: True
SourcePackage: flashcache
UpgradeStatus: Upgraded to raring on 2012-11-07 (143 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Martijn Dekkers (mdekkers)]

This seems to work for me:

cat << EOF > /usr/share/initramfs-tools/hooks/flashcache
#!/bin/sh

case \$1 in
prereqs)
        echo "dmsetup"
        exit 0
        ;;
esac

. /usr/share/initramfs-tools/hook-functions

mkdir -p \$DESTDIR/sbin
copy_exec /sbin/flashcache_create

manual_add_modules flashcache
EOF
chmod +x /usr/share/initramfs-tools/hooks/flashcache
cat << EOF > /etc/initramfs-tools/scripts/local-premount/flashcache
#!/bin/sh
/sbin/flashcache_create [YOUR FLASHCACHE CREATE COMMAND]
EOF
chmod +x /etc/initramfs-tools/scripts/local-premount/flashcache
update-initramfs -u

Please note that this works for me, and might not work for you, it might eat all your data, or cause your cat to eat your goldfish.

[Shahar Or (mightyiam)]

Thank you, Martin.

I reported this not much less than 2 years ago.

This was about my workstation.

By now I've gone fully SSD and that's what any sane workstation owner should do if possible.

[Martijn Dekkers (mdekkers)]

Hi Shahar, thanks for your note. We run this on a lot of servers, updating all of them to go fully SSD is expensive :)

I posted the script for posterity - it still appears to be an issue in Trusty