Ha! Thanks for this. I actually set it up yesterday only to get a critical error notice that the external disk just couldn't keep up (my translation of the jargon it spit out). I had to stop the transfer and make a hard restart of the laptop.
I am using a Thinkpad x200 and do intend on upgrading it via expresscard to USB 3.0. The external disk itself is USB 3.0 2 terabyte drive. FreeBSD was tested previously and works well. My draw to Dragonfly's is related to its NFS performance which seems to be consistently faster in my testing. I was also keen to experiment more with HAMMER outside of a virtual system. HAMMER's lower resource requirements are also a strong draw. On 12/17/2014 12:23 PM, Michael Neumann wrote: > > > Am 17.12.2014 um 03:52 schrieb Justin Sherrill: >> Short answer: yes, set up swapcache on the SSD and you'll benefit. >> That's the goal of swapcache. See the swapcache man page for a guide >> on how large to make your partition, and use the rest for / or however >> you want to arrange it. > > But keep in mind swapcache does not work as a write-cache. It's only > caching reads. > > USB 2.0 sets a limit which is higher than the 20 MB/sec you get, so I > assume it's your disk that is not the fastest (which I guess is quite > common for "USB" disks). I doubt you get more out of that disk on any > other operating system. > > FreeBSD/ZFS has something called ZFS Intent Log, which does write > caching. But I doubt you want to use it on your laptop as in general ZFS > is a bit more hungry in terms of resources. > > I'd suggest you to buy a good/fast harddisk and attach it via eSATA or USB 3.0 > (is it supported by DragonFly / your laptop?). Fast disks usually are powered > by an external power supply and not via the USB power (things might have > changed during the years). Swapcache can then help you to improve read > performance, which also helps write performance as it takes off read load from > the disk. A good harddisk should be able to give your 100 MB/sec of sequential > writes, but for random reads the performance is abysmal, this is where the SSD > shines. > > Regards, > > Michael
