On 08/25/2020 06:19 PM, Michal Soltys wrote:
On 8/25/20 7:42 AM, Xiao Ni wrote:
Hi all
Now mkfs on raid10 which is combined with ssd/nvme disks takes a long
time.
This patch set tries to resolve this problem.
Hi Michal
Are those fixes also possibly related to the issues I found earlier
this year about it's very weird discard handling whenever the
originating request wasn't essentially chunk-aligend ?
I searched by your email in my email box and I didn't find emails from
you at earlier this year. Is there a link? Discard request is usually
very big.
If the discard request is not chunk aligned, raid10 can handle this
problem without my patch. It splits I/O by chunk size and write/discard
this chunk to all copies.
What I found back then is e.g. discard of 4x32gb raid10 taking good 11
minutes via blkdiscard w/o explicit step option.
4x32gb means 4 disks and each disk is 32GB?
For the discard time problem, as mentioned just now, it splits big
discard request into small chunks. So it takes very long time.
My patch resolves this problem.
I still have blktraces of that available, the relevant thread part
with further more detailed followups can be found at:
https://www.spinics.net/lists/raid/msg62115.html
It's a raid456 problem, not raid10.
Regards
Xiao
