View Single Post
  #9   (View Single Post)  
Old 19th May 2009
jggimi's Avatar
jggimi jggimi is offline
More noise than signal
 
Join Date: May 2008
Location: USA
Posts: 6,256
Default

Quote:
Originally Posted by sherekhan View Post
RAIDframe or ccd?
For software RAID, use RAIDframe, for now. Its eventual replacement will be softraid(4), but today softraid does not have any way to recover from a storage device loss, the admin must back up the degraded array and recreate it, which can require many hours of down time. Plus, the only RAID available is a variant of RAID 1. (Crypto is another capability of softraid, but that doesn't apply to this discussion.)

The ccd facility is simpler to set up, but it cannot guarantee integrity after a failure, as it does not do parity checking on restart; it is my understanding that depending on the type of failure, that even mirroring (RAID 1) cannot assure integrity.
Quote:
it also seems to require a lot of planning and work to set up.
Not a lot, but yes, some planning is required. Running it in a test bed prior to making the switch gives one a great deal of confidence, however.
Quote:
Especially if I need a custom kernel every time I upgrade OpenBSD on the box.
No, that's not too all that hard either. The basic steps are to update your source tree, build the new kernel, boot it, then manually upgrade by un-tarring all but the *etcNN.tgz file sets per FAQ 4.10, then running sysmerge(8). In addition, each release's Upgrade Guide has a section on upgrading without the install kernel that you can use, with a little thought, as guidance.

In my case, I run -current on my RAIDframe system, so I "upgrade" by building the kernel and userland, then running sysmerge.
Quote:
I feel that I am left with two options: 1) Make my own live CD with everything I need, and 2) use something that is _not_ OpenBSD.
There are many other options. Assuming you can't restore directly from the ramdisk kernel, there are still other options. Here's just a few:
  • full system on USB drive/stick; directly booted or booted from install media
  • full system on LAN
  • boot ramdisk kernel, install full system on temporary storage
  • boot ramdisk kernel, dd restore of functioning system
Quote:
Following jggimis links there are tutorials and hints on how to make your own live CD, and I may end up doing this no matter what just for the experience
Making one's own is doable. I've been chatting with Stephan Rickauer (bsdanywhere.org) about jointly developing a "build-your-own-live-media" port/package for OpenBSD. We may do so in the next few months, if we can find the time.
Quote:
What I am not certain about is file system compatibility and bootloader.
There are significant differences between the filesystems -- there has been 14 years of divergent development between these systems. Data integrity/recoverability cannot be assured if you are doing filesystem restores. The same might be said of dump(8), as well.

The bootloaders are entirely different, as well. Even if you can possibly restore an OpenBSD filesystem from an OpenBSD dump from a FreeBSD system, something I doubt, you will need to install boot blocks (PBR) after the restore, and for that, you will need a running OpenBSD system. See installboot(8).
Reply With Quote