EVMS changes direction

Posted Nov 6, 2002 22:01 UTC (Wed) by Peter (guest, #1127) [Link]

This means if we use evms on a 2.4 system, we can't experiment with a 2.5 kernel. Unfortunate.

Welcome to my world. (: I use LVM, so until DM was included in the 2.5 kernel I couldn't test it - LVM did not survive the block device changes in 2.5.1 and 2.5.2, so it has been broken for basically the whole series.

Besides, if you read the message carefully, you'll note that Kevin is hoping to complete the changeover in early 2003 and will continue to maintain the current kernel patch until then.

At that point, in order to boot both 2.4 and 2.5 kernels you will have to figure out how to make two versions of the userspace tools coexist and select themselves when the appropriate kernel boots. Again - welcome to my world. LVM was like this for quite awhile in the 2.2 and 2.3 days - I used four different versions of its rapidly evolving ABI, with four sets of userspace tools, during that time. I hacked up the LVM tools to do this detection / selection, and a very similar approach was eventually implemented in the Debian packaging. It's annoying but doable. Quite possibly the EVMS maintainers will actually do that part for you; if not, perhaps someone like Debian will.

Oh, I forgot: they said they'll also be supporting DM on 2.4 kernels, so when the fateful flag day comes, you could just recompile your 2.4 kernel with the device mapper patch.