3 ms·
It's easier to get alignment right if you use raw disk, especially if you then run dmcrypt on top of your RAID. Unaligned partitions is a common source of bad
by knorker 8y ago
It's easier to get alignment right if you use raw disk, especially if you then run dmcrypt on top of your RAID.
Unaligned partitions is a common source of bad performance, and it's not a thing that (used to) "just work".
Therefore I've seen "don't use partitions" not be recommended, since it's otherwise a source of potential unalignment.
- rwmj 8y agoThis hasn't been a problem since around 2008 when all OS vendors changed their partitioning tools to use at least 1M alignment by default. I also wrote a tool (http://libguestfs.org/virt-alignment-scan.1.html http://libguestfs.org/virt-alignment-scan.1.html) which can be used to scan and in a few cases correct for this problem.
- sevensor 8y agoIncidentally, thank you for all your work on libguestfs! It's spectacularly useful.
- justinclift 8y agoAs a side point, I've seen mention recently that 1M alignment may not be optimal in some cases either. The recommendation was to use 4M instead, which apparently worked 100%. Just wish I could remember where I read that. I remember taking it on board as it made sense and the source seemed very credible.