5400rpm vs 7200rpm use for Parity or Storage

[mbc0]

Hi, I was lucky enough to pick up a Barracuda Pro 6TB for £115 and have also bought a Barracuda 6TB (non-pro) 

 

The largest drive in my 48TB array is currently 3TB so I have to make one of them Parity

 

I have 10gbE network speeds so would benefit from the read speeds if I used the the pro as storage but am leaning on thinking that I would get better overal performance if I used the Pro for Parity? so I am interested in any opinions?

 

Many Thanks

[Vr2Io]

No big different, when the fastest disk in Parity, the actual write speed still limit by the slowest disk read speed.

For performance gain, you must opt-out the slowest disk first.

[SSD]

39 minutes ago, mbc0 said:

Hi, I was lucky enough to pick up a Barracuda Pro 6TB for £115 and have also bought a Barracuda 6TB (non-pro) 

 

The largest drive in my 48TB array is currently 3TB so I have to make one of them Parity

 

I have 10gbE network speeds so would benefit from the read speeds if I used the the pro as storage but am leaning on thinking that I would get better overal performance if I used the Pro for Parity? so I am interested in any opinions?

 

Many Thanks

 

Read speeds are gated by the data disks speed and the network speed. So you'd get marginally faster speed from faster data drives.

 

Writes speeds are gated by slowest of the parity disk write speed and data disk write speed. So if your parity is slow, it will drag down write performance of every data disk.

 

Generally people tend to prefer to have a bit faster parity as a higher priority to have a fast data disk, but it depends on your use case.

[mbc0]

Thanks for your reply, what do you mean by opt-out the slowest disk first?

 

Forgot to mention I use a 1TB SSD as cache for all my shares but understand that only runs overnight to the array but see what you are saying about being in parity or storage, do you mean just remove slowest drives from my array by opting out?

 

[Vr2Io]

5 minutes ago, mbc0 said:

Thanks for your reply, what do you mean by opt-out the slowest disk first?

 

Forgot to mention I use a 1TB SSD as cache for all my shares but understand that only runs overnight to the array but see what you are saying about being in parity or storage, do you mean just remove slowest drives from my array by opting out?

 

 

Yes, for me, I wil 1st remove the most slowest disk ( or the oldest disk ) from array, no matter it is parity or data disk.

If all disk almost same speed or age, then I will consider place fastest disk in data disk instead of parity disk.

[mbc0]

Many Thanks for all your replies, I think for me it will be better to use the pro for parity as I have so many 3TB drives for data and slowly replace them with faster 6TB's

[pwm]

4 hours ago, Benson said:

No big different, when the fastest disk in Parity, the actual write speed still limit by the slowest disk read speed.

 

When writing to multiple data disks, it's an advantage to have a fast parity drive since the parity drive will multiplex between the different write tasks.

[mbc0]

Interesting Point... thank you!

[Vr2Io]

2 hours ago, pwm said:

 

When writing to multiple data disks, it's an advantage to have a fast parity drive since the parity drive will multiplex between the different write tasks.

It won't change / help, any slowest data disk will slow down in write operation. For multiple writing, it just mean extream slow.

Edited July 26, 2018 by Benson