topic Re: Chance of increased snap limits? in Array Performance and Data Protection

Chance of increased snap limits?

bubbagump41 — Sun, 11 Jun 2017 19:51:52 GMT

We are using replication between Nimble arrays on NImbleOS 3.7. The default Volume Collection replica count is two. Seeing that Veeam is going to manage our replicas, I thought I would be clever and set the retention on the arrays to "999". After setting a few Volume Collections to 999 the GUI started throwing this error:

Which leads me to believe that there are quotas under the covers I am not aware of. From some Googling I found some old 2.x articles saying there is a 10,000 snap limit which seems like what I ran into in 3.x. A) Are there plans to raise this limit? I'd love to keep a week's worth of hourly backups across all volumes. Let's say 100 volumes x 168 snaps = ~17000 snaps. C) It appears the per volume collection limit is a hard set 150 snaps. Can this be changed or will it be increased in future releases? An hourly snap for a week is at least 168. An every 15 minute snap (hooray super low RPO requirements ) for a week puts us at 672 snaps.

Sure feels like 100k snap limit and 1000/volume collection is something to shoot for if not already on the roadmap.

Re: Chance of increased snap limits?

jcates98 — Mon, 12 Jun 2017 13:10:40 GMT

So here's a neat command to use in order to better understand limits:

Nimble OS $ group --list_limits

With that, you can get a sense of an object's limits within various scopes (snapshots per volume, snapshots per group, snapshots per pool, snapcolls per volcoll, etc.) along with where you stand with regards to that limit. You'll see what your current usage is, what the warning threshold is, and what the actual maximum is.

Re: Chance of increased snap limits?

Nick_Dyer — Fri, 16 Jun 2017 08:41:45 GMT

It's worth noting that snapshot limits have been significantly increased since that old document you found. On some arrays such as the AFAs we support 500K snapshots per array!

Re: Chance of increased snap limits?

milovanov88 — Thu, 22 Jun 2017 14:04:31 GMT

I believe more explanation is needed. There is a concept of high and low retention per volume.

The snapshot limit of Nimble OS 2.3.x is at it's maximum over 150,000 snapshots.

Low retention is 150 or less. High retention is over 150 until 1000. Volume count limit on 2.3.x is 1024.

For high retention, you may only have up to 10 volumes with up to 1000 snapshots each.

For low retention, you could have remaining up to 1014 volumes with 150 snapshots.

1014 * 150 + 10 * 1,000= 152,100 + 10,000 = 162,100 snapshots are possible.

The limits in the command described above would not be as verbose as the Administration Guide, which is available on InfoSight. I would encourage to recheck the Administration Guide for each Nimble OS newer than 2.3.x for it's limits and or considerations.

Re: Chance of increased snap limits?

bubbagump41 — Wed, 05 Jul 2017 16:28:47 GMT

This is very helpful. The way it is presented now it seems like the GUI is saying... high retention, ZOMG we're all going to die!!!! Rather than a kind indicator just to let you judge in the scheme of the universe where the snapshot limit lies. Thanks!