Prisma VPN -- NAS download huge files very slow

krishnarandadath — Tue, 04 Aug 2026 17:03:11 GMT

Prisma VPN access -- SMB2 CIFS Files download from NAS dead slow. it takes, 24 to 38 hours for a 250 GB file to download --- any suggestions please.

Re: Prisma VPN -- NAS download huge files very slow

kiwi — Wed, 05 Aug 2026 10:35:09 GMT

Hi @krishnarandadath ,

If you're doing inspection then SMB download is slow by design. Check the following article on why SMB is slow and possible workarounds:
https://live.paloaltonetworks.com/t5/community-blogs/why-is-smb-traffic-slow/ba-p/356471

The firewall typically pins the entire SMB session to a single DP (Data Plane) CPU core. That core spikes to 100% capacity trying to do deep packet inspection on every single sequential block of the 250 GB file. As the single CPU core falls behind, the firewall's internal buffers fill up. It starts dropping packets, causing TCP window sizes to collapse. SMB interprets this network congestion by slowing itself down to a crawl to avoid losing data.

You can check this using the CLI 'show running resource-monitor':
How to Interpret: show running resource-monitor

As per the blog I shared above try DSRI or app-override (if possible)

Kind regards,

Re: Prisma VPN -- NAS download huge files very slow

krishnarandadath — Wed, 05 Aug 2026 18:40:14 GMT

Thanks a lot Kiwi, I will update you, what works in our environment.

topic Re: Prisma VPN -- NAS download huge files very slow in Next-Generation Firewall Discussions

Prisma VPN -- NAS download huge files very slow

Re: Prisma VPN -- NAS download huge files very slow

Re: Prisma VPN -- NAS download huge files very slow