Thanks in advance for any pointers!
Just yesterday I installed ubuntu desktop 16.04.02 32 bit on an existing system previously running 64 bit 12.04. I installed system and user data to a new SSD in the expectation of performance improvements.
Symptoms are severe lagging & unresponsiveness under any kind of sustained IO load. Rebooting the system seems to clear the symptoms for a while.
- Using rsync to copy 00's of GB of user data from a HDD to the user partition on the SSD took all afternoon and that was only after deliberately interrupting rsync and rebooting, periodically
- Using mksquashfs as part of preparing an ltsp installation caused multiple running procs to be killed, then the system froze completely, requiring a hard reset. The operation did complete afterwards, but only by running it on a completely quiet system. There's 16 GB RAM in the box, so available RAM wasn't an issue!
- From a user point of view applications "pause" when starting, and UI effects seem to wait a few seconds before completing.
Monitoring IOWAIT shows readings of 25 - 50% typically under load, and the write speed to the SSD drops from maybe 200 - 300 MB/s to 2 MB/s!
How would I go about starting to investigate the causes and do something about it? There must be something stupid I've done or not done along the way.
My fstab is:
The SSD was on /dev/sdd during the installation, but I moved some SATA cables around inside the box and now it is on /dev/sda. The /dev/sdaa in the fstab is swap on a legacy raid 0 partition md1 which is mount on demand (no idea at all why that is there, but the installer seems to have insisted on putting it there).Code:# <file system> <mount point> <type> <options> <dump> <pass> # / was on /dev/sdd1 during installation UUID=09979c08-9b79-4c49-a5b3-9138dc872623 / ext4 noatime,discard,data=ordered,errors=remount-ro 0 1 # /home was on /dev/sdd6 during installation UUID=83d3174a-99a1-4f3f-b469-9098ff601b26 /home ext4 noatime,discard,data=ordered,defaults 0 2 # swap was on /dev/sda1 during installation UUID=b8ee76ff-a1df-45ce-961e-bf53c9a37992 none swap sw 0 0 # swap was on /dev/sdd5 during installation UUID=bf886f6a-1407-4a69-b4bd-d06ea5232b02 none swap sw 0 0
Some useful information:
Code:~$ df -kh Filesystem Size Used Avail Use% Mounted on udev 7.9G 0 7.9G 0% /dev tmpfs 1.6G 9.6M 1.6G 1% /run /dev/sda1 92G 8.3G 79G 10% / tmpfs 7.9G 178M 7.8G 3% /dev/shm tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 7.9G 0 7.9G 0% /sys/fs/cgroup /dev/sda6 1.8T 614G 1.1T 37% /home tmpfs 1.6G 60K 1.6G 1% /run/user/1000Code:~$ sudo hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 18580 MB in 2.00 seconds = 9302.80 MB/sec Timing buffered disk reads: 860 MB in 3.00 seconds = 286.42 MB/secForgot to add the SSD is a Crucial_CT2050MX300SSD1 (M0CR031), and root and /home are both on the SSD, under separate partitions.Code:~$ sudo hdparm -v /dev/sda /dev/sda: multcount = 0 (off) IO_support = 0 (default) readonly = 0 (off) readahead = 256 (on) geometry = 249281/255/63, sectors = 4004704368, start = 0
Here's the output from bonnie++ running as default:
Code:Version 1.97 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP aammscott 32G 751 99 23076 2 91499 11 2553 100 280175 18 3697 43 Latency 22050us 127ms 160ms 3606us 39999us 15383us Version 1.97 ------Sequential Create------ --------Random Create-------- aammscott -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 6710 5 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ Latency 1154us 854us 1232us 375us 12us 32us 1.97,1.97,aammscott,1,1496730064,32G,,751,99,23076,2,91499,11,2553,100,280175,18,3697,43,16,,,,,6710,5,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,22050us,127ms,160ms,3606us,39999us,15383us,1154us,854us,1232us,375us,12us,32us
Adv Reply
Bookmarks