Creating a new raid group with 3TB SATA disks in existing aggregate with 2TB SATA

[KDEAN1961]

Hello,

Some background:

Running 8.1.2  7 mode on FAS 6280

2 Aggregates currently exist

1 =  SAS 600GB 10K drives

1 = SATA 2TB 7200 drives (4 raid groups x 20 disks) Total space is 124TB

We purchased 2 - 3TB SATA trays ( 48 total disks)  and assisigned 24 disks to each head

My question is this

Would like to create a NEW raid group  (20 x 3TB drives )in the existing SATA aggregate versus creating a new aggregate  due to existing volumes need to be expanded.

I understand the max size of the aggregate is 162TB

Does anyone see an issue with this in regards to performance.  Or is is recommended I create a whole new aggregate?  Just avoiding having to move volumes around.

Thanks

Kathy

[JGPSHNTAP]

Kathy,

It all depends on your need.  Do you need to grow your current aggregate.  Can you easily migrate volumes to another aggregate.

As the drives get larger, i always get a little leary on having such big raid groups with sata disks.  I've been burned when i lost a 40TB aggr with rg 20 disks on a triple disk failure due to the moos drive issue a few years back.

Also, do the drives right size down when you mix and match? I think they do.

I vote for new aggregate with smaller rg's.

But, I tend to be more risk adverse

[scottgelb]

I agree completely.... create a new aggregate and keep all drive sizes the same whenever possible.

[KDEAN1961]

If you create a new raid group the sizes will not size down.  That only happens if you mixed the sizes in the same raid group.

It is not easy for us to move volumes around thus why I want to expand the existing aggregate.

[KDEAN1961]

If I do create a new aggregate I am working with 24 disks.  Would it be best to create 2 raid groups with 11 disks in each and that leaves 2 spares? Or create 1 raid group with max of 20 diks and that leavs 4 spares/

[JGPSHNTAP]

20 would be my absolute top with 3TB drives. 

You are burning 2 drives.. hence other 2 are for spares.

Rebuild time would be 27+hrs.   Tread lightly with larger drives, that's all i'm saying..