It turns out that the clever idea of moving the swap partition to a USB flash drive had no effect whatsoever; the UI continued to freeze up during OpenSCAD compiles and suchlike, with the drive activity light on solid and not much in the way of swap activity. Sooo, I wondered what would happen with the
/tmp directory on non-rotating memory.
Then I spotted a sale on a Samsung 840 EVO 120 GB solid state drive, which seemed like it might improve almost everything in one swell foop. That’s a tiny drive, at least by contemporary standards, but all my data files live downstairs on the file server, so the desktop drive holds just the Xubuntu installation.
It’s worth noting that SSDs tend to fail suddenly and catastrophically, so that if the only copy of your data is on that drive, there is no recovery. In this case, I’d lose some configuration that changes with every installation, a few locally installed / compiled-from-source programs, and little else.
The nice thing about transferring a Linux installation: boot a live CD image (I used Ubuntu 14.04LTS, the same as the desktop box), copy the files to the new drive, set up Grub, and you’re back on the air. That recipe worked fine, although I used
rsync -au to copy the files and then updated
/etc/fstab with the SSD’s new UUID (rather than duplicate a supposedly unique ID).
The Grub recipe does require a bit of delicate surgery, so I removed the OEM hard drive and rebooted the live CD image before doing this. If the SSD fell victim to a finger fumble, I could just start over again:
sudo mount /dev/sda1 /mnt for f in dev proc sys usr ; do sudo mount --bind /$f /mnt/$f ; done sudo chroot /mnt sudo update-grub sudo grub-install /dev/sda sudo grub-install --recheck /dev/sda exit for f in dev proc sys usr ; do sudo umount /mnt/$f ; done sudo umount /mnt
Then reboot from the SSD and It Just Worked.
Dropbox and DigiKam noticed the UUID change and asked for advice; there’s no need for re-registration, re-activation, or re-authorization.
The overall time from boot to login isn’t much shorter, because of the tedious delay while the network and the NFS shares get up & running, but the desktop UI startup zips right along.
The same OpenSCAD compile that previously brought the UI to a halt has no effect, so I hereby declare victory. I think the complex solid models that used to take forever will see much the same speedup.
The Dell hard drive (an ordinary 7200 RPM 3.5 inch brick) lies abandoned in place under the fancy black shroud; the Optiplex 980 layout butts the drive’s right-angle SATA connectors hard against the CPU heatsink and offers no spare SATA power connectors. There was just enough room to wedge the SSD above the PCI connectors, where it won’t get into any trouble:
The hard drive contains the never-used Windows 7 partition and the corresponding recovery / diagnostic partitions; keeping the drive with the Optiplex chassis seems like a Good Idea.