System on SSD

[Sven Gaerner]

Hi,

just some notes about the current state migrating to an SSD for the system.

I installed the SSD, created a GPT partition on it that contains the following
layout.
  a:  1 GB UFS
  b: 40 GB swap
  d:  8 GB HAMMER
  e: 10 GB unused

Currently only swap is used by swapcache. That indeed speed up things like
tab-completion, searching for files and build pkgsrc a lot. But I did not run
an benchmarks or speed comparison tests.

UFS should contain /boot and the rest of the system (/usr and /var) will go on
the HAMMER filesystem. Any PFSs that are heavily modified will stay on another
HDD.

Before using the SSD for the system I tried migrating the system from an
older and smaller HDD to a bigger one. I used the following steps, that are
also described in [1] and the gpt man page.

 * partition the new disk
 * use cpdup to copy /
 * remove any links in /pfs via rm
 * run "hammer mirror-copy /olddisk/pfs/usr /newdisk/pfs/usr"
   to mirror /usr
 * do the same for var, var.tmp, ...
 * adjust HAMMER configuration of usr.obj, var.tmp, tmp by running
   "hammer viconfig /pfs/usr.obj" and set snapshots to "0d 0d" to
   disable them completely
 * adjust /etc/fstab (mainly change the serial number of the disk :))
 * run boot0cfg to make the new disk bootable

That's all to copy the system. Most of the time is waiting for the mirror-copy
command to finish.

Sven

[1] http://www.dragonflybsd.org/docs/howtos/howto_reinstall_hammer/