How to check maximum disk read & write operations of SSD in m & gb

z_haseeb · 10-12-2022, 01:41 AM

How to check maximum disk read & write operations of SSD in mb & gb
We have a Linux machine and see RAM/CPU SWAP is not using more than 50%. However the disk %iowait is 8 to 11. The disk claim its 500 plus read & write operations(picture is attached). The disk is SSD. Below snapshot of iowait is for a reference

04:59:47 PM CPU %user %nice %system %iowait %steal %idle
04:59:48 PM all 20.20 0.00 4.95 8.81 0.00 66.03
04:59:49 PM all 19.05 0.00 4.46 7.88 0.00 68.61
04:59:50 PM all 20.31 0.00 5.20 9.71 0.00 64.77
04:59:51 PM all 22.07 0.00 4.66 9.05 0.00 64.22
04:59:52 PM all 20.34 0.00 4.25 8.42 0.00 66.99
04:59:53 PM all 20.62 0.00 4.74 10.10 0.00 64.54
04:59:54 PM all 21.77 0.00 4.86 10.81 0.00 62.56
04:59:55 PM all 19.06 0.00 4.23 11.27 0.00 65.44
04:59:56 PM all 20.60 0.00 4.37 9.69 0.00 65.35
04:59:57 PM all 21.66 0.00 5.18 10.49 0.00 62.67
04:59:58 PM all 18.99 0.00 3.98 7.54 0.00 69.50
04:59:59 PM all 23.47 0.00 6.04 9.27 0.00 61.22
05:00:00 PM all 25.91 0.00 6.25 7.63 0.00 60.21
05:00:01 PM all 25.33 0.00 5.63 7.34 0.00 61.70
05:00:02 PM all 24.56 0.00 6.84 9.71 0.00 58.89

z_haseeb · 10-12-2022, 02:00 AM

Iowait & iostat output

Guttorm · 10-12-2022, 09:05 AM

There is a tool called nmon which can give you better information about which disk is being used and how much is read/written. Install it, run nmon and hit "d".

Also, htop is not a good tool for IO. Try iotop instead - showing the processes where the process using the most IO is "the winner" - not the one using the most CPU. It also shows how much it reads and writes.

z_haseeb · 10-13-2022, 02:04 AM

Thanks for your response. I don't need to know which process is utilizing the disk thru IOTOP or NMON. I also dont want to know what is the current disk read & write while the disk is busy in reading and writing.
MY QUERY
I want to know a tool which can show the maximum read & write speed of SSD

mrmazda · 10-13-2022, 02:38 AM

Code:

# hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   16136 MB in  1.99 seconds = 8099.80 MB/sec
 Timing buffered disk reads: 1500 MB in  3.00 seconds = 499.38 MB/sec

z_haseeb · 10-13-2022, 02:55 AM

This command seems good but I can see it only show read status. Does this command shows any statistics for write ?

PHP Code:


			
Timing cached reads
Timing buffered disk reads

Guttorm · 10-13-2022, 04:23 AM

If you want to test it, you can use a tool like dd.

https://www.cyberciti.biz/faq/howto-...th-dd-command/

syg00 · 10-13-2022, 06:24 AM

Quote:

Originally Posted by z_haseeb

TI want to know a tool which can show the maximum read & write speed of SSD

Any I/O benchmark suitable for SSD should suffice.

I suspect yet another example of an xyproblem - what problem are you trying to solve ?. What workload is being impacted ?.

z_haseeb · 10-13-2022, 07:05 AM

Actually I can see read/write performance is few MB/sec (check thru IOTOP) and disk is busy 90% (check thru IOSTAT). But when I run the dd command the read/write is excellent like more than 1 GB read/write. So thats why I asked in above post "how to check maximum read/write speed of SSD" to know the benchmark OR dd command is enough

Few ofthe above members also recommend dd command which seems fine for me