Not sure what's going on with not being able to register again - not a lot of info to go off of. It was working last I checked in the bcache-3.2-dev branch, it might be buggy in the older bcache branch. >From your numbers it looks like the 8 gb of data wasn't in the cache - bcache bypasses sequential IO by default. You can flip it off by echoing 0 to sequential_cutoff. On Tue, Feb 14, 2012 at 9:26 PM, Franco <franco@xxxxxxxxxxxxxxxx> wrote: > Hi > > I was in the process of testing linux-bcache but was seeing some strange > behaviour so I thought I would remount my cached filesystem. I then > noticed that the performance results started looking like the cache just > wasn't there, so I unregistered it: > > bcache: Cache set be008612-38aa-4082-9f42-1bada25cb002 unregistered > bcache: Caching disabled for sdc > > but now when I try to register it again, I get bcache: error > opening /dev/sdb: device busy. > > I haven't tried rebooting yet but probably will do after I've sent this > message. > > These were the strange results I was getting that prompted me to unmount > and remount the filesystems. > > Setup: hardware RAID 5 16 disk array with 2 partitions, 1 Intel 40GB SSD > for bcache. > > Filesystem Size Used Avail Use% Mounted on > /dev/bcache0 1.9T 26G 1.8T 2% /data33 > /dev/sdd 1.9T 23G 1.8T 2% /data34 > > Wrote an 8GB file to each filesystem, then tried reading it back. > Machine has 8GB RAM. > > Speed for random reads from identical SSD = 181.766523 MB/Sec, random > read test done in the following order with measured speed in MB/Sec. The > random IO is actually just reading with a 4GB stride, wrapping around at > the end of the file. > > /data33 49 > /data34 114 > /data33 114 > /data33 and /data44 simultaneously 78 and 59 respectively > /data33 76 > /data33 68 > /data34 114 > /data34 96 > /data34 69 > /data34 74 > /data33 118 > /data33 40 > /data34 91 > > After remounting both filesystems: > > /data34 148 > /data33 120 > /data34 120 > /data33 82 > > > After unregistering the cache > > /data33 65 > /data34 83 > /data33 99 > /data34 113 > > Cheers, > Franco > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
