Benchmarking Disks Reading and Writing Capacity

We already know how to measure the speed of our Ethernet through this article I wrote using iperf. Now let’s measure the speed of our records, very useful to identify eventual Bacula backup bottlenecks.

Linux Reading (FD):

The dd command can be used to measure the read speed of a file, as in the following example.

echo 3 | sudo tee /proc/sys/vm/drop_caches
time dd if=/mnt/<moont>/<big_file> of=/dev/null bs=8k

Another nice software to do that is hdparm.

sudo hdparm -Tt /dev/sda


 Timing cached reads:   12960 MB in  2.00 seconds = 6484.97 MB/sec
 Timing buffered disk reads: 398 MB in  3.00 seconds = 132.56 MB/sec

The values ​​for each execution may suffer a small variance for each execution, but serve as a good parameter to know the ability to verify machines with Bacula Clients.

Leitura Windows  (FD):

Open an elevated command prompt: click Start and type cmd in the search box.

Right-click cmd and select Run as administrator.

In the command prompt window, type:

winsat disk -drive c

…where ‘c’ is the unit you want to test).

You should see a response similar to the following:

Benchmarking Disks Reading and Writing Capacity 1


Linux Writing (SD):

In this case, we will use the old dd again.

dd if=/dev/zero of=/tmp/output bs=8k count=250k; rm -f /tmp/output

256000+0 records in
256000+0 records out
2097152000 bytes (2,1 GB) copied, 16,5959 s, 126 MB/s

I chose 250k granularity to have significant total data for the test (2.1 GB) , but a larger test size may be more accurate and compatible with your actual workload .

If you do not have a file system still on disk, you can run the test as follows:

dd if=/dev/zero of=/tmp/output bs=8k count=10k; rm -f /tmp/output

The end!




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