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In the last article, I talk about an ssd vs hdd comparison which you can be found here. In this article, I will spend sometime to learn into samsung ssd 850. Samsung ssd 850 pro is a solid state drive. At this moment, this drive produced a staggering of IOPS 100,000 read IOPS and 90,000 write IOPS[19] . Support sata interface of 6gigabits per seconds.
Additional characteristics of this model.
4 KB aligned random I/O at QD32
10,000 read IOPS, 36,000 write IOPS at QD1
550 MB/s sequential read, 520 MB/s sequential write on 256 GB and larger models
The capacity for this model range from 128GB, 256GB, 512GB, 1024GB, 2048GB. A 2.5inch form factor with a dimension of 100W x 69.85H x 6.8D in millimeter. The primary storage is made of Samsung 3-core MEX controller with DRAM as the caching memory. Caching memory size with respect to the ssd capacity are 256 MB (128 GB) or 512 MB (256 GB & 512 GB) or 1 GB (1 TB) LPDDR2 or 2 GB LPDDR3 respectively. From the official sites, the following performances are outlines.
With this blazing speed, as for me as a software engineer, I really think the speed help me in term of application launching like eclipse and especially code grepping or file finding. But I think this speed is definitely a ideal match for software like cassandra and elasticsearch where disk I/O speed is much sought after. With the number show above and with my previously hdparm comparison, I think it will give very much difference if switch from normal hdd spinning disk to this ssd.
Full support for TRIM, garbage collection, and SMART technology are guaranteed. With a staggering reliability of 2 million hours mean time between failures and 150Terabytes written and TEN YEARS warranty period, I must say I am impressed and convinced. The power consumption is also very low. During active read/write, maximum of 3.5W and 3.0W respectively. If you are using this for laptop which power is always a matter of concern, ssd is a wise decision.
With 24 awards under the belt for this model, I think for the skeptical section of people, it is safe to really start to use ssd. If you have a budget, I think rather than just up the cpu and ram, a switch from hdd to ssd should give very much difference too.
I leave this article with samsung 850 pro ssd videos
There are many article online that articulate how fast a solid state drive in comparison to a spinning hard disk drive. But ones wonder really, just how fast is ssd. I mean if your earning is limited and the current spinning disk is working fine, there is no compelling reason to make the change and at the same time, it will be difficult to afford a ssd considering the cost per gb. As of this writing, a samsung 850 pro 512GB selling at compuzone malaysia at a staggering pricing of 1378MYR!!! But there is a kind soul who generously donate ssd to me and as a gesture of good will back to him, here in I will write a blog describe my experience migrating from a Hitachi/HGST Travelstar Z7K500 HGST HTS725050A7E630 to a Samsung SSD 850 PRO 512GB.
One things for sure, ssd weight is so light. It is only 66gram! In comparison with hdd at 95gram. For the first timer, ssd weight is so light that it confused me like did it actually contain the size of 512GB.
For the spinning hdd, I took 5 samples, 1min 41sec, 1min 34sec, 1min 34sec, 1min 34sec and 1min 31sec. All measurements from the moment I push the power button until I see the login screen. Of cause, there many services running during bootup. On average, the bootup time is around 1min 48sec.
Next, I benchmark the current hdd with hdparm and dd.
I have performed 3 tests with cache and without cache reading. On average, non caching read speed is about 107.12MB/sec and caching read speed is 2867.80MB/sec . The parameter for hdparm is shown below.
-t Perform timings of device reads for benchmark and comparison purposes. For meaningful results, this operation should be repeated 2-3 times on an otherwise inactive system
(no other active processes) with at least a couple of megabytes of free memory. This displays the speed of reading through the buffer cache to the disk without any prior caching of data. This measurement is an indication of how fast the drive can sustain sequential data reads under Linux, without any filesystem overhead. To ensure accurate measurements, the buffer cache is flushed during the processing of -t using the BLKFLSBUF ioctl.
-T Perform timings of cache reads for benchmark and comparison purposes. For meaningful results, this operation should be repeated 2-3 times on an otherwise inactive system
(no other active processes) with at least a couple of megabytes of free memory. This displays the speed of reading directly from the Linux buffer cache without disk access. This measurement is essentially an indication of the throughput of the processor, cache, and memory of the system under test.
Next, I use command dd to do higher layer benchmark on the disk. See below.
user@localhost:~$ time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile
250000+0 records in
250000+0 records out
2048000000 bytes (2.0 GB) copied, 32.5028 s, 63.0 MB/s
real 0m41.773s
user 0m0.068s
sys 0m4.048s
user@localhost:~$ time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile
250000+0 records in
250000+0 records out
2048000000 bytes (2.0 GB) copied, 27.1676 s, 75.4 MB/s
real 0m37.012s
user 0m0.056s
sys 0m3.848s
user@localhost:~$ time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile
250000+0 records in
250000+0 records out
2048000000 bytes (2.0 GB) copied, 19.4599 s, 105 MB/s
real 0m37.929s
user 0m0.064s
sys 0m3.740s
So the arithmetic, ( 8 x 1024 x 250000 / 2014 / 1024 ) / real so that give 46.75MB/sec, 52.77MB/sec and 51.49MB/sec respectively on all three tests and on average 50.33MB/sec.
Now to the samsung ssd.
root@localhost:~# sudo hdparm -t /dev/sda6
/dev/sda6:
Timing buffered disk reads: 770 MB in 3.01 seconds = 256.00 MB/sec
root@localhost:~# sudo hdparm -t /dev/sda6
/dev/sda6:
Timing buffered disk reads: 762 MB in 3.00 seconds = 253.98 MB/sec
root@localhost:~# sudo hdparm -t /dev/sda6
/dev/sda6:
Timing buffered disk reads: 758 MB in 3.00 seconds = 252.44 MB/sec
root@localhost:~# sudo hdparm -T /dev/sda6
/dev/sda6:
Timing cached reads: 5820 MB in 2.00 seconds = 2910.31 MB/sec
root@localhost:~# sudo hdparm -T /dev/sda6
/dev/sda6:
Timing cached reads: 6022 MB in 2.00 seconds = 3011.33 MB/sec
root@localhost:~# sudo hdparm -T /dev/sda6
/dev/sda6:
Timing cached reads: 5698 MB in 2.00 seconds = 2849.14 MB/sec
root@localhost:~#
root@localhost:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile
250000+0 records in
250000+0 records out
2048000000 bytes (2.0 GB) copied, 4.14268 s, 494 MB/s
real 0m8.280s
user 0m0.040s
sys 0m2.084s
root@localhost:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile
250000+0 records in
250000+0 records out
2048000000 bytes (2.0 GB) copied, 4.18595 s, 489 MB/s
real 0m8.279s
user 0m0.068s
sys 0m2.036s
root@localhost:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile
250000+0 records in
250000+0 records out
2048000000 bytes (2.0 GB) copied, 3.94227 s, 519 MB/s
real 0m8.258s
user 0m0.080s
sys 0m2.060s
On average, non caching read speed is 253.67MB/sec and caching read speed is 2926.93MB/sec. As for dd tests, on average, 236.10MB/sec. On average, the bootup time is around 30sec! The significant change is during after grub and the login shown is around 3 seconds or less. Although the rated for this ssd for sequantil read and write is 550/520MB/sec, maybe it was because of my old system bandwidth maxing out.
Significant time reduced during bootup and disk read is clearly seen from the statistics above. As for user experience, everything become so fast! To put into comparison, hdd to ssd is like proton car to F1 car. I think in the future, it will help in term of programming like code grepping and code find.
UPDATE: with adjustment to the grub timeout and changes to the POST to fast boot, now my cold boot to login screen is improved to 20seconds!
