Hi Keld,
On 10/10/18 8:07 PM, keld@xxxxxxxxxx wrote:
Hi Guoqing
Yes, near is the default, but some have suggested that far be made the default.
Far has about double the reading speed as near, while writing speed is only a little less.
https://marc.info/?l=linux-raid&m=141104637932757
So a number of people have said that "far" has the best overall performance, but then
I think that "far" is not so well known in the community, still 10 years after its
implementation in the kernel. I was the inventor of the "far" layout.
Good to know it :-)
here are my ideas for writing grow support for raid10 far layout (at the end)
https://marc.info/?l=linux-raid&m=130288632726912&w=2
I will read it and see if what I can do something, thanks.
Cheers,
Guoqing
Best regards
keld
On Wed, Oct 10, 2018 at 09:37:49AM +0800, Guoqing Jiang wrote:
Hi Keld,
On 10/9/18 8:25 PM, keld@xxxxxxxxxx wrote:
Hi
Are you thinking of also doing enhanced support for plain raid10?
For example raid10 far layout lacks growing support.
Yes, I am aware of that, this patchset is for clustered raid10 which only
support near layout so far.
I once wrote up some ideas on how to implement growing support for raid10
far layout -
it was posted on this list, but if you are interested I can send it again.
Thanks, please send it to me or let me know the key word then I can search
it.
BTW: I am curious if there are lots of people want to grow raid10 with far
layout, after all, the layout is n2 by default.
Regards,
Guoqing
best regards
keld
On Tue, Oct 09, 2018 at 10:59:41AM +0800, Guoqing Jiang wrote:
Hi,
This series aim to change the capacity for clustered raid10
just like normal raid10.
The first patch ensure all nodes have the same bitmap size
before reshape. After that, master node broadcasts RESYNCING
msg in reshape_request and slave nodes update reshape_position,
this is achieved by the second patch.
The 3rd patch addes sanity check for resync_info_get, and
other patches are introduced to handle different kinds of
cases which happened during grow clustered raid10. And the
last patch cleans up suspend_info which is not necessary.
Thanks,
Guoqing
Guoqing Jiang (8):
md-cluster/raid10: resize all the bitmaps before start reshape
md-cluster/raid10: support add disk under grow mode
md-cluster: introduce resync_info_get interface for sanity check
md-cluster/raid10: call update_size in md_reap_sync_thread
md-cluster/raid10: don't call remove_and_add_spares during reshaping
stage
md-cluster/bitmap: don't call bitmap_sync_with_cluster during
reshaping stage
md-cluster: send BITMAP_NEEDS_SYNC message if reshaping is interrupted
md-cluster: remove suspend_info
drivers/md/md-cluster.c | 234
++++++++++++++++++++++++++++++++----------------
drivers/md/md-cluster.h | 2 +
drivers/md/md.c | 65 ++++++++++++--
drivers/md/md.h | 1 +
drivers/md/raid10.c | 81 ++++++++++++++++-
5 files changed, 297 insertions(+), 86 deletions(-)
--
2.12.3
