If you had installed your RHEL/CentOS 5 system using LSILogic Parallel controller, you may have noticed the horrible I/O performance…
You unfortunately cannot just change the controller type and expect your VM to boot. There is a few easy steps to ensure that the OS can boot with the new controller.
FIRST thing FIRST : Do a snapshot BEFORE doing any of these steps, if something goes wrong your system may not boot properly.
1. Make sure you have VMware Tools installed [show me how]
2. If you do have VMware Tools installed, make sure you have the pvscsi module installed (this step is only required if you want to use the Paravirtualized controller (recommended). Go to step 3 if you want to use LSI SAS)) :
rpm -qa | grep pvscsi
This should return the following result if they are installed :
vmware-tools-pvscsi-common-9.10.0-5.el5
kmod-vmware-tools-pvscsi-1.2.3.0-2.6.18.8.el5.5.el5
If they aren’t installed, simply do :
yum install vmware-tools-pvscsi-common kmod-vmware-tools-pvscsi
3. Edit the modprobe configuration :
/etc/modprobe.conf
And replace replace all the “scsi_hostadapter” with the following :
alias scsi_hostadapter mptbase alias scsi_hostadapter1 mptscsih alias scsi_hostadapter2 mptfc alias scsi_hostadapter3 mptspi alias scsi_hostadapter4 mptsas alias scsi_hostadapter5 pvscsi
4. You can optionally backup the kernel image – if you do have a snapshot this isn’t absolutely necessary :
cp /boot/initrd-$(uname -r).img /boot/initrd-$(uname -r).img.bak
5. Rebuild the kernel image/initrd :
mkinitrd -f -v /boot/initrd-$(uname -r).img $(uname -r)
At this point, no error should have been seen on the console output. You can see the following in the end :
[…]
Adding module scsi_mod
Adding module sd_mod
Adding module scsi_transport_spi
Adding module mptbase
Adding module mptscsih
Adding module mptspi
Adding module scsi_transport_fc
Adding module mptfc
Adding module scsi_transport_sas
Adding module mptsas
Adding module pvscsi
[…]
6. You may now shutdown your VM and change the controller type and start your VM again.