On 08/02/2011 09:01 AM, Alexander Graf wrote:
On 02.08.2011, at 15:45, Shribman, Aidan wrote:
Subject: [PATCH v3] XBZRLE delta for live migration of large memory apps
From: Aidan Shribman<aidan.shrib...@sap.com>
By using XBZRLE (Xor Binary Zero Run-Length-Encoding) we can reduce VM downtime
and total live-migration time for VMs running memory write intensive workloads
typical of large enterprise applications such as SAP ERP Systems, and generally
speaking for representative of any application with a sparse memory update
pattern.
On the sender side XBZRLE is used as a compact delta encoding of page updates,
retrieving the old page content from an LRU cache (default size of 64 MB). The
receiving side uses the existing page content and XBZRLE to decode the new page
content.
Work was originally based on research results published VEE 2011: Evaluation of
Delta Compression Techniques for Efficient Live Migration of Large Virtual
Machines by Benoit, Svard, Tordsson and Elmroth. Additionally the delta encoder
XBRLE was improved further using XBZRLE instead.
XBZRLE has a sustained bandwidth of 1.5-2.2 GB/s for typical workloads making it
ideal for in-line, real-time encoding such as is needed for live-migration.
How does this compare to just doing gzip compression for the same workload?
Regards,
Anthony Liguori
