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Performance effect of NTFS Compression on Network

Hi all

A minor problem that I'd love to find an answer for, just for reliability reasons.

System:  Dell R320 server with Windows 2012 R2 Essentials.  RAID1 SATA disks with a H310 controller, no write-back cache. Cisco small business grade switch.

Originally I stumbled on an issue where I was getting terrible write performance over the network (<1Mb/s) when writing large files (eg 5Gb) from client to server.  After a bit of reading, I changed the Disk Cache Policy to Enabled on the controller and now the same operation is lightning fast.

However, I since discovered a minor caveat.  Consider this:

  •     An uncompressed 5Gb file is written from a client PC to the server over the network
  •     The destination on the server is an NTFS compressed folder
  •     There is no perceived CPU bottleneck on the server during write (ie <10% total utilization)
  •     Network utilization on the server appears to not be saturated during transfer
  •     Another PC playing a .WAV file across the network from a different uncompressed server location will experience audio "stuttering" at the same time
  •     There is no "stutter" when the same scenario is repeated writing to a non-compressed folder.


I would like to solve is the "stutter" on other desktops.  Obviously turning off compressed folders is a fix, but I'd like to understand the root cause to eliminate potential reliability problems as best I can.

My thoughts do come back to Disk Controller performance.  I had the same "stutter" issue during BOTH compressed and uncompressed writes BEFORE changing the Disk Write Cache policy to Enabled.  But in my mind there is something else not right.  Both writes now have noticeably better network throughput than before and server resources appear to be unstressed so I can't explain why compression is having such an effect, and is it a hardware or OS issue.

I'm going to play with the network adapter properties and driver updates and see what happens, but I'd love some other suggestions and if anyone has seen something like this before!

Marty

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