vinum in 4.x poor performer?

Marc G. Fournier scrappy at hub.org
Tue Feb 8 21:32:34 PST 2005


On Tue, 8 Feb 2005, Dan Nelson wrote:

> Details on the array's performance, I think.  Software RAID5 will
> definitely have poor write performance (logging disks solve that
> problem but vinum doesn't do that), but should have excellent read
> rates.  From this output, however:
>
>> systat -v output help:
>>     4 users    Load  4.64  5.58  5.77
>
>> Proc:r  p  d  s  w    Csw  Trp  Sys  Int  Sof  Flt
>>     24     9282       949 8414*****  678  349 8198
>
>> 54.6%Sys   0.2%Intr 45.2%User  0.0%Nice  0.0%Idl
>
>> Disks   da0   da1   da2   da3   da4 pass0 pass1
>> KB/t   5.32  9.50 12.52 16.00  9.00  0.00  0.00
>> tps      23     2     4     3     1     0     0
>> MB/s   0.12  0.01  0.05  0.04  0.01  0.00  0.00
>> % busy    3     1     1     1     0     0     0
>
> , it looks like your disks aren't being touched at all.  You are doing
> over 99999 syscalls/second, though, which is mighty high.  The 50% Sys
> doesn't look good either.  You may have a runaway process doing some
> syscall over and over.  If this is not an MPSAFE syscall (see
> /sys/kern/syscalls.master ), it will also prevent other processes from
> making non-MPSAFE syscalls, and in 4.x that's most of them.

Wow, that actually pointed me in the right direction, I think ... I just 
killed an http process that was using alot of CPU, and syscalls drop'd 
down to a numeric value again ... I'm still curious as to why this only 
seem sto affect my Dual-Xeon box though :(

Thanks ...

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy at hub.org           Yahoo!: yscrappy              ICQ: 7615664


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