Re: scrub backing device

[ching <lsching17@gmail.com>]

for example https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-scrub

On May 12, 2016 3:13:22 AM GMT+08:00, Eric Wheeler <bcache@lists.ewheeler.net> wrote:
>On Wed, 11 May 2016, ching lu wrote:
>
>> The read cache prevent the program to scrub the backing device
>directly.
>> 
>> if a few bits flipped in the backing device, the cache may still
>> return healthy data for a while.
>> 
>> Must i remove cache device before scrubbing?
>
>What do you mean by scrub?
>
>--
>Eric Wheeler
>
>> 
>> 
>> On Wed, May 11, 2016 at 9:15 AM, Eric Wheeler
><bcache@lists.ewheeler.net> wrote:
>> > On Fri, 29 Apr 2016, ching lu wrote:
>> >
>> >> Hello,
>> >>
>> >> i want to develop a script to perform data scrubbing periodically.
>> >
>> > I think you want to set dirty_percent to 0 and
>cache_mode=writethrough.
>> > Then wait a long time for dirty_percent to actually reach 0.
>> >
>> > --
>> > Eric Wheeler
>> >
>> >
>> >>
>> >> For my use case, i think it is meaningless to scrub cached data.
>> >>
>> >> If i change the cache mode to "none", will it turn off the read
>cache too?
>> >>
>> >> Furthermore, will this invalidate cached data? (i do not want to
>"warm
>> >> up" the cache again after the scrubbing)
>> >>
>> >> Thanks in advance,
>> >> c
>> >> --
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