SSD performance problems -- config problem or old drive?

[chconnor]

Hey, out of curiosity, what do you get on your 840 Pro for:
sudo smartctl -a /dev/sda | grep Total_LBA | awk '{print $10}'

I'm only at 30k hours but I do a fair amount of file I/O (lots of time lapses with thousands of files :-) ) and I'm just idly curious to see if it's more or less than yours.

While we're at it, what about:

sudo smartctl -a /dev/sda | grep Wear_Leveling | awk '{print $4}'

...I'm at 88%.

[claydoh]

Is it possible, or rather likely, that the differences seen between the OSs are due to different benchmarking tools being used in each one?

[chconnor]

Thanks a bunch --

If you're testing on NTFS, I would expect poor results. It's a crappy file system and not native to Linux.

Yeah my problem has always been that I dual boot between windows and I've never found a better option to share partitions between the two. I.e. the support in windows for linuxy filesystems has always been worse than the support in linux for windowsy filesystems. :-) If there are any alternatives, I'm all ears!

I'll look into those ext4 options and see if I can improve things at all, thanks.

Re-running kdiskmark I'm getting results closer to yours, so it may have been a transitory issue...

As far as the lagging, I doubt it's the drives. More likely NTFS and file indexing - which you can turn off - or let run until it's finished.

The thing is that it has only started recently, after 8ish years of being fine. It's not terrible lagging, just every now and then things hanging longer than they used to. E.g. saving a text file in emacs that used to be instant now pauses for a few seconds, or opening a dolphin window takes a couple seconds before the contents appear, etc... stuff that kinda feels like the disk is held up doing something. Maybe a recent update has caused some kind of issue.

You're not running your installation from a NTFS partition are you?

No, / and /home are of course ext4. It's just the dual-boot shared data partitions that are NTFS. I do, however, symlink some stuff from the ext4 partitions to the ntfs partitions, due to limited space on / and /home, e.g. firefox cache, but nothing that I think would explain this...

[oshunluvr]

Off the top I would say, yes that's too slow for a Samsung 840 Pro, but mine isn't much better (same tests):
My Samsung 840 Pro drive (45000+ power on hours, probably same age as yours):

[Read]
 541.341 MB/s [    528.7 IOPS] 
 494.982 MB/s [    483.4 IOPS] 
 196.398 MB/s [  49100.7 IOPS]
  35.857 MB/s [   8964.5 IOPS] 

[Write]
 505.046 MB/s [    493.2 IOPS] 
 438.812 MB/s [    428.5 IOPS] 
 174.436 MB/s [  43610.0 IOPS]
 122.764 MB/s [  30691.1 IOPS]

Benchmark utilities aren't really worth much except to compare raw results. Not much of what they test spills over into the real world.

If you're testing on NTFS, I would expect poor results. It's a crappy file system and not native to Linux. That we can read/write to it is a hack at best IMO. EXT4 can be tuned - there's dozens of articles on how to. I use btrfs which is generally slower than EXT4 but my results are better than yours.

My EXT4 partition has these mount options: noatime,data=writeback,barrier=0,nobh,errors=remou nt-ro
For some reason the Forum software is inserting that extra space in "remount-ro". We're due for an upgrade soon.

I also shrunk the reserved blocks to 0 instead of the default 5% because it's not a system partition, just used for virtual drive storage.

Just for fun, here's my Samsung 970 Pro NVME drive:

[Read]
3193.470 MB/s [ 3118.6 IOPS] 
1610.199 MB/s [ 1572.5 IOPS] 
 746.689 MB/s [ 186673.2 IOPS] 
  57.107 MB/s [ 14276.8 IOPS] 

[Write]
1763.246 MB/s [ 1721.9 IOPS] 
1443.867 MB/s [ 1410.0 IOPS] 
 155.535 MB/s [ 38884.9 IOPS]
 136.145 MB/s [ 34036.4 IOPS]

As far as the lagging, I doubt it's the drives. More likely NTFS and file indexing - which you can turn off - or let run until it's finished. You're not running your installation from a NTFS partition are you?

BTW, here's a one-liner that will run hdparm on all your drives:

for dr in `lsblk -d |grep -v -- 'loop\|sr\|NAME'`; do sudo hdparm -Tt '/dev/'$dr; done

[chconnor]

Hi! I recently noticed some sporadic lagging in my system (20.10 on an i4770K) and I thought "maybe a disk is acting up." I have a few SSD's and a few HDD's on this system. Using KDiskMark, I found the SSDs (one of which contains / and /home and /win for a dual boot into Windows 8.1) are apparently running extremely slow. They are pretty old drives (on the order of 8 years?), so maybe that's all it is?

The tests being run are:

Sequential 1 MiB (Q= 8, T= 1)
Sequential 1 MiB (Q= 1, T= 1)
Random 4 KiB (Q=32, T=16) (*on Windows CrystalDiskMark this test is T=1)
Random 4 KiB (Q= 1, T= 1)

/ and /home (Samsung 840 Pro) are showing:

[Read]
540.731 MB/s
320.208 MB/s
191.349 MB/s
2.803 MB/s

[Write]
372.830 MB/s
291.069 MB/s
79.786 MB/s
2.923 MB/s

...however the results aren't super consistent when I re-run them other times.

A different partition on the same disk is getting:

[Read]
429.211 MB/s
452.952 MB/s
32.538 MB/s
5.770 MB/s

[Write]
260.469 MB/s
296.476 MB/s
55.664 MB/s
92.254 MB/s

That third partition, when I run CrystalDiskMark in the Windows installation, gets much better results: >550 MB/s sequential reads, 389 MB/s random 4k reads (instead of 32 on linux!) and similarly the write speeds are 2-3 times as fast as on linux. The partition is NTFS; I could see the windows driver being faster than linux's driver, but that much faster? And why would the ext4 partitions be so slow on linux?

Similar stuff is happening on the second SSD, a Samsung 860 EVO: sometimes performance is about the same, but usually it's much faster on Windows, and sometimes 2-3 times as fast (also an NTFS partition.)

Any thoughts on what might be happening?

/etc/fstab is pretty vanilla:
UUID=1234 / ext4 errors=remount-ro 0 1
UUID=1235 /home ext4 defaults 0 2
UUID=1236 /otherpartition ntfs defaults,umask=007,gid=46,uid=1000 0 0

The SSDs have the latest firmware.

SMART checks and self tests and so on reveal nothing.

If it was just a tired old disk, it wouldn't magically run so much faster on Windows, right?

/home is encrypted, but not / (their results are the same in KDiskMark).

Any thoughts are greatly appreciated!