[DRBD-user] [Q] Does drbd affect how blockdev --setra is applied?

Maurice Volaski mvolaski at aecom.yu.edu
Thu May 26 16:06:56 CEST 2005

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Where does applying blockdev --setra fit in regard to drbd, 
particularly if one is running drbd over lvm? The post below (from 
the LVM mailing list) says it must be set across the entire I/O 
subsystem.

(A later post clarified that optimum performance occurred when it was 
set to > 0 at the lv layer and zero for both device and md layers.)

Also, does anyone know where the values get stored when they are 
applied to the device itself?

>  >>Hi Guys,
>>>
>>>Should one set blockdev --setra on the lvm device, on the individual
>>>block devices making up the lvm device or both?
>>>
>>>
>>>   
>>>
>>
>>Interesting question. Answer to that IMHO depends on the internal kernel
>>structures.
>>
>>Isn't the easisest aproach to try and see what happens ?
>>
>>Regards,
>>
>>Branko
>> 
>>
>
>  From experimentation: set it on everything.
>device, md, lv
>
>David

-- 

Maurice Volaski, mvolaski at aecom.yu.edu
Computing Support, Rose F. Kennedy Center
Albert Einstein College of Medicine of Yeshiva University



More information about the drbd-user mailing list