topic Re: Slow Read Performance in ONTAP Hardware

Slow Read Performance

JamaMax — Wed, 04 Jun 2025 10:00:59 GMT

We have FAS2729 NetApp Release 9.9.1P7 72 disk x 14.TB used for CommVault Backup disk library. There is 80 iSCSI LUN presented to Windows 2016 servers.

The read performance is terrible, our vendor is working with NetApp support but no progress at all.

Re: Slow Read Performance

paul_stejskal — Thu, 19 May 2022 15:15:28 GMT

Those utilities like ATTO Disk Benchmark or Crystalmark are for directly attached drives on laptops/desktops, not JBOD/SAN/NAS drives. What is your case number and I will check on current status?

When looking at issues like this, it is important to know expectations/normal too. Also this is a great KB we've tried to make as customer friendly as possible: https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Software/ONTAP_OS/ONTAP_9_Performance_-_Resolution_Guide

Re: Slow Read Performance

JamaMax — Thu, 19 May 2022 16:03:21 GMT

Hi Paul thank for your replay, what tool do you recommend to run from Windows server the test read performance, I'm also working with CommVault support but they utility shows max read speed of 37MB/s . I guess that write performance is better because it's hitting the FAS cache

we have 1024 GB on each node

Re: Slow Read Performance

paul_stejskal — Thu, 19 May 2022 19:48:05 GMT

Benchmarks shouldn't be used to diagnose perf problems. They only should be used to identify the maximum capable throughput. What is the actual problem leading up to this?

Re: Slow Read Performance

JamaMax — Thu, 19 May 2022 20:55:06 GMT

the restore is very slow when reading from NetApp LUN

Re: Slow Read Performance

paul_stejskal — Fri, 20 May 2022 14:48:03 GMT

https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Software/ONTAP_OS/ONTAP_9_Performance_-_Resolution_Guide

Please follow above and see where the slowest latency is seen. If you need more involved support please open a case or we can discuss on Discord.

Re: Slow Read Performance

JamaMax — Tue, 24 May 2022 17:00:11 GMT

Hi Paul thanks for replay the vendor is working with NetApp support now

Re: Slow Read Performance

paul_stejskal — Tue, 24 May 2022 17:05:06 GMT

Nice. If you have any suggestions on how to improve the KB please let us know. If there was something that could not be found there to help you resolve I'd like to fix it for others in the future.

Thank you.