Return
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Title
NDMP 'Direct Access Restores' Slow for EMC Isilon OneFS 7.0.x Filers -
Description
With 3-way and remote data transfer models, NDMP restores using Direct Access Restore (DAR), the data transfer rates are very slow on EMC Isilon OneFS 7.0.x filers. -
Cause
The reason for the slow performance is that the host ACK delay (or TCP delay in unix) from DMA affects the restore performance. Usually hosts will set the ACK delay to 200ms so that multiple packets can be received before an ACK is sent out. Which means that the Isilon filer we can only send 1 packet every 200ms. -
Resolution
1. Disable TCP ACK delay when running 3-way DAR on the DMA (NetVault: Backup Server).
Here are various links with steps to accomplish this:
https://support.microsoft.com/en-us/kb/823764
http://lifeandcode.net/2009/05/reduce-game-network-latency-in-windows-7-or-vista/
http://kb.globalscape.com/KnowledgebaseArticle10438.aspx
2. Do not use 'Direct Access Restore' by using the Restore Option 'Never Do Direct Access Restore'.