Re: Extremely poor disk performance on ProLiant DL360 G5 RAID

[mlelstv%serpens.de@localhost (Michael van Elst)]

frank%phoenix.owl.de@localhost (Frank Wille) writes:

>On Fri, 20 Jul 2018
>mlelstv%serpens.de@localhost wrote:

>> Write operations on these servers have always been slow if the RAID
>> controller doesn't have a working battery backup unit (BBU).

>Good to know! Thanks.

>Which means, as soon as I install such a BBU, the write-operations would
>magically and immediately become fast?

>If only such a BBU wouldn't be so hard to find... :|

BBU modules should be available from places that sell refurbished
servers. The battery itself usually needs to be replaced every 1-2 years :-/

>Is there no hack to simulate the presence of a BBU?

Maybe you can enable write caching of the disk drives, that would
improve speed at the cost of somewhat reduced reliability.
If you use WAPBL setting vfs.wapbl.flush_disk_cache=0 may help
with the same caveat.

RAID-1 should also be significantly faster than RAID-5 in this case.


-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."