POHMELFS Encryption

Jeremy — Fri, 11 Jul 2008 22:36:23 +0000

Evgeniy Polyakov announced the latest release of his Parallel Optimized Host Message Exchange Layered File System, POHMELFS. He noted that the big new feature in this release is strong crypto support, "one can specify [an] encryption method (like cbc(aes), hash or digest, or all of them to be performed on [the] whole data channel (except headers)." In his blog, Evgeniy adds, "Cryptography support is [an] essential addition to the POHMELFS core. It was implemented with performance in mind, so that processing speeds would not drop noticeably even [during] very CPU-hungry operations". He explained, "POHMELFS utilizes [a configurable number of] pools of crypto threads, which perform data crypto processing and submit it either to [the] network or VFS layer." He included results from some performance benchmarks.

Evgeniy describes POHMELFS as "a high performance network filesystem with [a] locally coherent cache of data and metadata. Its main goal is distributed parallel processing of data. [The filesystem] supports [a] strong transaction model with failover recovery, allows encryption/hashing [of the entire] data channel, and performs read load balancing and write to multiple servers in parallel." When asked on his blog when he plans to push the new filesystem for mainline kernel inclusion, Evgeniy noted, "I do not know, maybe its time to push it upstream, but I do not want to bother with Linux kernel politics. We will see soon."

POHMELFS Performance

Jeremy — Mon, 16 Jun 2008 16:56:06 +0000

"I regularly run and post various benchmarks comparing POHMELFS, NFS, XFS and Ext4, [the] main goal of POHMELFS at this stage is to be essentially as fast as [the] underlying local filesystem. And it is..." explained Evgeniy Polyakov, suggesting that the POHMELFS networking filesystem performs 10% to 300% faster than NFS, depending on the file operation. In particular, he noted that it still suffers from random reads, an area that he's currently focused on fixing. He summarized the new features found in the latest release:

"Read request (data read, directory listing, lookup requests) balancing between multiple servers; write requests are sent to multiple servers and completed only when all of them send an ack; [the] ability to add and/or remove servers from [the] working set at run-time from userspace; documentation (overall view and protocol commands); rename command; several new mount options to control client behaviour instead of hard coded numbers."

Looking forward, Evgeniy noted that this was likely the last non-bugfix release of the kernel client side implementation, suggesting that the next release would focus on adding server side features, "needed for distributed parallel data processing (like the ability to add new servers via network commands from another server), so most of the work will be devoted to server code."

KernelTrap - POHMELFS

POHMELFS Encryption

POHMELFS Performance