Testing the Samsung MU-PA500B 500GB SSD

Solid State

Performance Roundup

Traditionally, the first look at a drive's block performance is taken with the omnipresent dd(1) tool [8]. Aside from its ubiquity, the ability to benchmark an unpartitioned drive might come in handy. This is a sequential write benchmark, so never write to the drive's device file (e.g., sdb) directly unless you actually intend to erase the partition (Figure 3). hdparm [9] also includes a built-in benchmark that is aware of caching and buffering [10]. hdparm is also a powerful resource to configure internal drives, but although this is not possible over USB, it can be used to turn disk caching on or off (-W) over a SATA bus.

Figure 3: Simple disk benchmarks with dd and hdparm.

Finally, I'll complete the quick inspection by checking the drive's I/O latency with ioping [11]. Just like its network namesake, ioping continues to read from a defined filesystem path until interrupted, reporting its results at the end (Listing 3). You can expect an average 200ms of latency on small reads from this remarkable external device.

Listing 3

ioping

federico@cybertron:~$ sudo ioping /media/federico/Samsung_T5/
4 KiB <<< /media/federico/Samsung_T5/ (fuseblk /dev/sdb1): request=1 time=94.8 us (warmup)
4 KiB <<< /media/federico/Samsung_T5/ (fuseblk /dev/sdb1): request=2 time=202.2 us
4 KiB <<< /media/federico/Samsung_T5/ (fuseblk /dev/sdb1): request=3 time=200.4 us
4 KiB <<< /media/federico/Samsung_T5/ (fuseblk /dev/sdb1): request=4 time=221.4 us
^C
--- /media/federico/Samsung_T5/ (fuseblk /dev/sdb1) ioping statistics ---
3 requests completed in 623.9 us, 12 KiB read, 4.81 k iops, 18.8 MiB/s
generated 4 requests in 3.35 s, 16 KiB, 1 iops, 4.77 KiB/s
min/avg/max/mdev = 200.4 us / 208.0 us / 221.4 us / 9.51 us

Infos

Jerry Pournelle: https://en.wikipedia.org/wiki/Jerry_Pournelle
MU-PA500B: https://www.amazon.com/gp/product/B073GZBT36/
mount(8) man page: https://linux.die.net/man/8/mount
fstab(5) man page: https://linux.die.net/man/5/fstab
"How to Mount and Unmount Filesystem/Partition in Linux" by Balakrishnan Mariyappan: https://www.thegeekstuff.com/2013/01/mount-umount-examples/
fdisk(8) man page: https://linux.die.net/man/8/fdisk
"Aligning filesystem partitions" by Federico Lucifredi, ADMIN , issue 19, 2014, pg. 96, http://www.admin-magazine.com/Archive/2014/19/Aligning-filesystem-partitions
dd(1) man page: https://linux.die.net/man/1/dd
hdparm(1) man page: https://linux.die.net/man/8/hdparm
"Tuning your filesystem" by Federico Lucifredi, ADMIN , issue 7, 2012, pg. 81, http://www.admin-magazine.com/Articles/Tuning-Your-Filesystem-s-Cache
ioping: https://github.com/koct9i/ioping/

The Author

Federico Lucifredi is the product management director for Ceph Storage at Red Hat, formerly the Ubuntu Server PM at Canonical, and the Linux "Systems Management Czar" at SUSE. He enjoys arcane hardware issues and shell scripting mysteries, and he takes his McFlurry shaken, not stirred. You can read more from him in the new O'Reilly title AWS System Administration .

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