Maximun RAID-size with or without Efficiency Features?

[Jan_Renz]

Hi,

I have a question regarding the maximum aggregate size as shown in the HWU.

In my case, I have a FAS2554, the maximun aggregate size is shown as 120 TiB.

Is it a physical limit (the amount of physical disk space of the underlying disk and written to them) or is it a soft limit (the sum of all data in the corresponding volumes)?

If it is a soft limit, what about efficiency features?

E.g. I have my aggregate filled up with 110 TiB, then I run a very good deduplication-job (1:3) and will be able to write additional 100 TiB in the aggregate...is this possible?

I guess it is a physical limit, but please let me know how to calculate with it.

BR
Jan

[pedro_rocha · Accepted solution]

Hi Jan,

Max Aggr Size in HWU is a soft limit that ONTAP imposes to your platform (FAS2750 is 400TB for example). There are other soft limits regarding number of volumes and their sizes.

Regarding your question, you are able to span that Aggr Max Size through dedup on the volumes inside that aggregate. But the physical size of the aggr will remain 120TB and supported as per the HWU.

You should pay attention to max vol sizes and count.

Regards,

Pedro Rocha.

[SpindleNinja]

It’s technically both!   There’s a max drive count, max capacity as well as a max aggr size.   And  depends which limit you hit first when it comes to the max drive count and max capacity count.     if you have 144 drives on your 2554 you’ve hit a limit.    But say those drives are 10TB and not 2TB. You could go over the max capacity count of the system.   

there’s also max aggr count, etc etc.  ONTAP is all software raid.    All maxes can be found at Hardware U.  Http://hwu.netapp.com

Storage eff doesn’t matter if the aggr can write 100TB, then it can write 100TB.  If 300TB of data get written in there using dedupe.  That’s a great 3:1 storage eff.  

[Jan_Renz]

Thank you guys!