[Gluster-users] Bitrot: Time of signing depending on the file size???

David Spisla spisla80 at gmail.com
Fri Mar 1 14:00:33 UTC 2019


Hello Amudhan,

Am Fr., 1. März 2019 um 14:56 Uhr schrieb Amudhan P <amudhan83 at gmail.com>:

> Hi David,
>
> Once after file write completes (fd closed) bitrot process will wait for
> 120 seconds and if there no fd is opened for the file it will trigger the
> signer process.
>
Yes, I already know this. But there is still the problem that a fd will no
closed after open() as bigger s file is. See link to discussion.

>
> considering the signer, process start and end time file read speed was <
> 250KB/s.
>
How can I measure this?

>
> To increase bitrot signer read speed need to modify the bitrot source file.
>
How can I do that?

Regards
David

>
> regards
> Amudhan
>
> On Fri, Mar 1, 2019 at 5:49 PM David Spisla <spisla80 at gmail.com> wrote:
>
>> Hello Amudhan,
>>
>> What does exactly mean "it takes < 250KB/s"?
>> I figured out this discussion between you and Kotresh:
>> https://lists.gluster.org/pipermail/gluster-users/2016-September/028354.html
>> Kotresh mentioned there that the problem is because for some files fd
>> process are still up in the brick process list. Bitrot signer can only sign
>> a file if the fd is closed. And according to my observations it seems to be
>> that as bigger a file is as longer the fd is still up. I could verify this
>> with a 500MiB file and some smaller files. After a specific time only the
>> fd for the 500MiB was up and the file still had no signature, for the
>> smaller files there were no fds and they already had a signature.
>>
>> Does anybody know what is the reason for this? For me it looks loke a
>> bug.
>>
>> Regards
>> David
>>
>> Am Fr., 1. März 2019 um 08:58 Uhr schrieb Amudhan P <amudhan83 at gmail.com
>> >:
>>
>>> Hi David,
>>>
>>> I have also tested the bitrot signature process by default it takes <
>>> 250 KB/s.
>>>
>>> regards
>>> Amudhan P
>>>
>>>
>>> On Fri, Mar 1, 2019 at 1:19 PM David Spisla <spisla80 at gmail.com> wrote:
>>>
>>>> Hello folks,
>>>>
>>>> I did some observations concerning the bitrot daemon. It seems to be
>>>> that the bitrot signer is signing files depending on file size. I copied
>>>> files with different sizes into a volume and I was wonderung because the
>>>> files get their signature not the same time (I keep the expiry time default
>>>> with 120). Here are some examples:
>>>>
>>>> 300 KB file ~2-3 m
>>>> 70 MB file ~ 40 m
>>>> 115 MB file ~ 1 Sh
>>>> 800 MB file ~ 4,5 h
>>>>
>>>> What is the expected behaviour here?
>>>> Why does it take so long to sign a 800MB file?
>>>> What about 500GB or 1TB?
>>>> Is there a way to speed up the sign process?
>>>>
>>>> My ambition is to understand this observation
>>>>
>>>> Regards
>>>> David Spisla
>>>> _______________________________________________
>>>> Gluster-users mailing list
>>>> Gluster-users at gluster.org
>>>> https://lists.gluster.org/mailman/listinfo/gluster-users
>>>
>>>
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