iscsi problems

[white_mike]

Hello there,
I have some questions. I apologize for the quality of my English I use the translator to help me ...

Version: FreeNAS 9.2.1.5
Hardware :
64GB RAM
36 x 3TB HD
2 Xeon e2620

Our pool consists of a stripe raidz (2 x 5HD)

1) We have hundreds of extents iSCSI right now but when adding / deleting it takes almost 30 minutes for the operation to be done and it causes performance drops at the same time. Is this normal? Is there a solution?

2) Is it possible to edit the database freenas to correct errors? In some datasets storage no longer functioning properly tab.

example:
I create a dataset in "Client1" on mypool / Dataset1 / and it will put in MySecondPool / Dataset1 / Exe / Client1

Do you have an idea to help me?

 

[white_mike]

anyone have idea ?

 

[cyberjock]

Sorry but there's too many factors. I'd make sure that your zpool is upgraded to the latest( # zpool upgrade <poolname> ).

The problem stems from the fact that when you delete something (file, etc.) the delete must be performed immediately. With iSCSI in particular the blocks used will be scattered all over the pool. If the pool is more than about 80% full it's MUCH worse. There was/is/will be a feature flag to make this not be a major problem, but not sure if it is something from the past or future. I can't get good info on the feature flags being developed and such anymore.

I'd say that most people don't have this problem because:

1. They don't delete extents very often. (Some places simply abandon the iscsi extents and let a script delete them at midnight or at the next maintenance cycle)
2. If you aren't overfilling your pool this problem shouldn't be particularly bad.
3. Many people that have problems with this are already operating overloaded FreeNAS boxes. I'd consider adding more RAM or an L2ARC to the box. ;) If I were you I'd go up to 96GB of RAM(128GB would be even better) and then drop in 240-480GB of L2ARC. Just don't make your L2ARC bigger than 5x your system RAM.

 

[white_mike]

ISCSI volumes are all on the same pool that is filled to 70%. We archive once it reaches 75%.
We are obliged to remove iscsi extents when checking out the server to avoid lists with half of invalid entries
For the RAM I always 5-10Go free is not enough?
I'll look for L2ARC.
Thank you for your help and answers.

 

[cyberjock]

The amount free is inconsequential. If you had 1TB of RAM you'd still have 5-10GB of RAM free. ZFS will take all that it can, without limits.