how would you layout 7 drives in a raidz pool

[fahadshery]

Hi,

I have a total of 7 1.8TB Enterprise SAS3 drives. How would you lay them out? I already have 2 x stripped mirror pools comprised of SSDs so I am just looking for capacity and not for performance!

thanks

 

[ChrisRJ]

Personally I would go for RAIDZ2 to have better resilience. With 1.8 TB and depending on the criticality of the data RAIDZ1 may be ok as well. But that is your call.

 

[fahadshery]

Personally I would go for RAIDZ2 to have better resilience. With 1.8 TB and depending on the criticality of the data RAIDZ1 may be ok as well. But that is your call.

thanks, will there be any benefits of doing the following over RAIDZ2:

1. 3 x disks in RAIDZ1 (1 vdev)
2. 4 x disks in RAIDZ1 (1 vdev)

thanks

 

[fahadshery]

what about fusion pools for performance? How could I set those up and what is required for that?

 

[adrianwi]

RAIDZ2

 

[joeschmuck]

thanks, will there be any benefits of doing the following over RAIDZ2:

1. 3 x disks in RAIDZ1 (1 vdev)
2. 4 x disks in RAIDZ1 (1 vdev)

thanks

Well that depends on what your needs are.

You should understand the RAIDZ2 has two drives of redundancy which is the first part that stands out to me.
The second part is, two RAIDZ1 vdevs will produce two vdevs that have one drive each of redundancy.

Capacities:
RAIDZ2 of seven 1.8TB drives = 8.4TB usable storage
RAIDZ1 of three 1.8TB drives = 3.6TB usable storage
RAIDZ1 of four 1.8TB drives = 5.2TB usable storage

RAIDZ1 total usable storage = 8.8TB usable storage

Or another option is RAIDZ1 of seven 1.8TB drives = 10.6TB usable storage

So you could have 8.4TB or 8.8TB, the difference is the 8.4TB has two drive redundancy. This makes the answer obvious to most people, RAIDZ2 of 7 drives. If your data is absolutely not important the you could run a RAIDZ1 as I laid out. But to ensure you don't hate yourself later, do the RAIDZ2.

(usable storage is minus 20% capacity to ensure the pool operates at a good sustained speed)

 

[fahadshery]

You should understand the RAIDZ2 has two drives of redundancy which is the first part that stands out to me.
The second part is, two RAIDZ1 vdevs will produce two vdevs that have one drive each of redundancy.

I was thinking more of when it will be time to upgrade storage capacity of the pool. For example: if I have a small vdev then its easier/cheaper to upgrade to bigger capacity disks and if I had 7 disks in RAIDZ2 then I need 7 disks to upgrade the whole pool.

So you could have 8.4TB or 8.8TB, the difference is the 8.4TB has two drive redundancy. This makes the answer obvious to most people, RAIDZ2 of 7 drives. If your data is absolutely not important the you could run a RAIDZ1 as I laid out. But to ensure you don't hate yourself later, do the RAIDZ2.

(usable storage is minus 20% capacity to ensure the pool operates at a good sustained speed)

I am not gonna go for a massive RAIDz1 pool for sure. I will accept your opinion of not hating myself later.

 

[Davvo]

R

thanks, will there be any benefits of doing the following over RAIDZ2:

1. 3 x disks in RAIDZ1 (1 vdev)
2. 4 x disks in RAIDZ1 (1 vdev)

thanks

This is bad. With 7 drives you want a single vdev.
Go RAIDZ2.

R2-C2

jro.io

 

[joeschmuck]

I was thinking more of when it will be time to upgrade storage capacity of the pool. For example: if I have a small vdev then its easier/cheaper to upgrade to bigger capacity disks and if I had 7 disks in RAIDZ2 then I need 7 disks to upgrade the whole pool.

True, I was thinking you purchased enough capacity to last the warranty period of the drives, I need to make some assumptions at times. However most people should be purchasing drives to meet or exceed the expected capacity requirement for the warranty period of the drives. I typically say to select a capacity that will last you 3 to 5 years, plus 50% extra (because we all like more space). This way when the warranty expires and if you need to replace a drive, you have the option of replacing the drives as they fail and still not running out of capacity, then when that last drive is replaced you gain the entire pool capacity. Also many people will replace all the drives once the first few die vice waiting years for them all to die. And some people will just replace all the drives to gain more capacity sooner.

Good luck in whatever you end up doing.