From 829b5e22345f6580216e176ccb7930cf84f6117f Mon Sep 17 00:00:00 2001 From: dillon Date: Mon, 15 Apr 2013 09:54:12 -0700 Subject: [PATCH] --- docs/developer/gsocprojectspage/index.mdwn | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/docs/developer/gsocprojectspage/index.mdwn b/docs/developer/gsocprojectspage/index.mdwn index 94c36544..7722accf 100644 --- a/docs/developer/gsocprojectspage/index.mdwn +++ b/docs/developer/gsocprojectspage/index.mdwn @@ -459,5 +459,22 @@ Meta information: * Difficulty: Moderate * Contact point: kernel@lists.dragonflybsd.org, Matthew Dillon +--- + +##### HAMMER2 - Add copies feature +Add block redundancy to HAMMER2 + +* hammer2 implements a fully set-associative indirect block table with dynamic radix, which means that the entries in an indirect block table have a lot of flexibility, including the ability to have redundant entries representing the same block. + +* Implement hammer2's copies feature which allows one to configure multiple volumes and to specify that more than one copy of the filesystem topology be maintained. This requires both a realtime piece to handle filesystem modifications in progress, and a batch piece to tie-up loose ends. for a GSOC the batch piece is the easiest to implement for writing purposes, with a realtime piece for reading (but not writing, which would be much more difficult). The batch piece would simply traverse the filesystem looking for missing copies and construct the missing copies in batch or semi-real-time. + +* Such an implementation would allow HAMMER2 to operate with redundant hard drives and for hard drives to be ejected and added (within reason) on a live system. + +Meta information: + +* Prerequisites: C, heavy kernel knowledge +* Difficulty: Hard +* Contact point: kernel@lists.dragonflybsd.org, Matthew Dillon + --- (please add) -- 2.41.0