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booting installed linux through iscsi
2018-08-08, 16:31
Post: #3
RE: booting installed linux through iscsi
If you are wanting to move a running installation of Linux on a local hard disk to an iSCSI LUN, you are going to have to do some fairly extensive work to accomplish the task;

I assume your iSCSI LUN is identified on the running installation as /dev/sdb (although it could be anything).

General Compatibility Checklist:

a. EFI Secure Boot to iSCSI is not currently possible.
b. Most newer Linux Distributions require that SELinux be disabled for iSCSI/NFS boot.
c. iSCSI boot with iPXE doesn't use GRUB or GRUB2, typically.
d. Your Linux Distribution of choice will need the development kernel, dracut and dracut-network installed before attempting to perform the migration.
e. Your kernel will need to be configured to support iSCSI/NFS boot and your initrd/initramfs will need to be rebuilt with the modified settings (particularly cached /etc/fstab, iSCSI and network settings).
f. You will need to edit your /etc/fstab to reflect the new disk mount points. This operation may need to be done before "e." above.
g. You will need to DD /dev/sda to /dev/sdb at some point.
h. iPXE will essentially become your bootloader, and you will need some sort of a boot script to accomplish the boot. I highly recommend writing the script with robust checks and error handling.

Closing thoughts:

It is easier to install to iSCSI than move a running Distribition to iSCSI (needed to say that).

Thin and Thick Clients should not share a single iSCSI mount unless it is Read Only. For this reason (and many others), I recommend using NFS Roots boot for Thin/Thick Clients in most cases. iSCSI is pretty messy protocol, and while it does work well, there are easier ways to get the functionality without some other overhead.


"Thus far, you have been adrift within the sheltered harbor of my patience..."
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RE: booting installed linux through iscsi - MultimediaMan - 2018-08-08 16:31

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