4x SSD Raid 0 Same Speed as 1x SSD

[mouzzampk]

Hi, I have 4 SSDs in Raid 0 and I am not seeing any speed improved comparison to single SSD. 

 

I hope attached image give some info but please let me know if you need more information.  

 

Thank you

[JorgeB]

hdparm only tests a device, not a pool, you can for example copy a large file to the pool then read it back with pv:

 

single device pool:

pv /mnt/cache/10.mkv > /dev/null
17.9GiB 0:00:38 [ 481MiB/s]

 

three device raid0 pool:

pv /mnt/temp/10.mkv > /dev/null
17.9GiB 0:00:14 [1.27GiB/s]

 

Note that this is an actual file read, so never as fast a synthetic benchmark but also gives more real world values, you can also test write speed by making the destination the pool and the source a fast device or a RAM disk.

 

Make sure the file is not cached to RAM after the first test, depending on the filesystem used an array re-start may suffice, in doubt do it after a fresh reboot.

[mouzzampk]

22 hours ago, JorgeB said:

hdparm only tests a device, not a pool, you can for example copy a large file to the pool then read it back with pv:

 

single device pool:

pv /mnt/cache/10.mkv > /dev/null
17.9GiB 0:00:38 [ 481MiB/s]

 

three device raid0 pool:

pv /mnt/temp/10.mkv > /dev/null
17.9GiB 0:00:14 [1.27GiB/s]

 

Note that this is an actual file read, so never as fast a synthetic benchmark but also gives more real world values, you can also test write speed by making the destination the pool and the source a fast device or a RAM disk.

 

Make sure the file is not cached to RAM after the first test, depending on the filesystem used an array re-start may suffice, in doubt do it after a fresh reboot.

Everyday learning something new  

 

Thank you

 

Edited May 13, 2023 by mouzzampk