[mythtv-users] RAID on Fedora Core 3?

[Max Waterman]

Looks like my RAID5 arrays have crap performance - esp. the master
array.

Is it something to do with the master/slave thing, or something else?

Comments?

Max.

/dev/md0 is 2xWD2000 SATA via m/b - RAID0
=========================================
       ------Sequential Output------ --Sequential Input- --Random-
       -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
  Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
    3G 49056  88 136360  33 38863  10 52577  88 115880  16 389.6   1
       ------Sequential Create------ --------Random Create--------
       -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
    16  2213  24 +++++ +++  6623  73  7286  67 +++++ +++  5289  57

/dev/md1 is 4xWD800 PATA RAID5 master array
===========================================
       ------Sequential Output------ --Sequential Input- --Random-
       -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
  Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
    3G 31272  59 34758   8  9009   3 16343  28 19788   3 265.3   1
       ------Sequential Create------ --------Random Create--------
       -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
    16   506   8 +++++ +++   574   7   530  10 +++++ +++   367   5

/dev/md2 is 4xWD2000 PATA RAID5 slave array
===========================================
       ------Sequential Output------ --Sequential Input- --Random-
       -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
  Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
    3G 44201  78 43174  11 14761   6 38522  67 66666  14 359.4   0
       ------Sequential Create------ --------Random Create--------
       -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
    16  1098  14 +++++ +++  1131  16  1118  17 +++++ +++  1006  15


Max Waterman wrote:
> Hi,
> 
> So, I did try this (two RAIDs, one as all master devices and one as all 
> slaves devices) and it seems to work OK.
> 
> I had a bit of a problem making the slave plugs reach the drives. With 
> all the drives as master devices, I got the full one meter length and 
> there was no problem, but the slave plug is not the full length and so 
> was a struggle. Far from ideal, but I'm short of cash, so I had to try.
> 
> What I am not sure about is the performance. I have run bonnie++ on the 
> arrays (plus another 2x250GB RAID0 array, running off the motherboard 
> SATA controller), but haven't really looked at the results. I'll post 
> them here tonight.
> 
> BTW, I was considering trading in my EIDE drives for 8xWD2000 SATA 
> drives and getting a Supermicro 8-port SATA controller :
> 
> http://www.supermicro.com/products/accessories/addon/DAC-SATA-MV8.cfm
> 
> It looks like just the job. Just thought I'd mention that board in case 
> other people have been looking for something similar. They tell me it 
> works on PCI as well as PCI-X.
> 
> Max.
> 
> Paul Barker wrote:
> 
>> Hi
>>
>>> I'll give it a try since the alternative (two 4 channel s/w RAID boards) 
>>
>> yet is more money ;)
>>
>> Cool, let me know how you get on. I'd be interested if it works !
>>  
>> Cheers
>>  
>> Paul
>>  
>>
>>
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