[lug] Feedback Wanted - Proposed Open Source Disk Test SW

[George Sexton]

If I'm getting what you're saying, as long as I seed the PRNG with the 
same value at the start of the write, and the start of the compare, then 
I could use the stream from the re-initialized PRNG for comparison

Steve Sullivan wrote:
> George,
> 
> One way to have every block, and in fact every word, be different would be:
> 
>   main:
>     seed = argv value to integer
>     rng = new RNG
>     writeFile( rng, seed)
>     readFile( rng, seed)
> 
>   writeFile( int seed):
>     rng.setSeed( seed)
>     for a while:
>       write rng.getInteger()
> 
>   readFile( int seed):
>     rng.setSeed( seed)
>     for a while:
>       read value
>       if value != rng.getInteger(): error()
> 
> Steve
> 
> On Wed, Jan 02, 2008 at 09:49:59PM -0700, George Sexton wrote:
>>
>> Steve Sullivan wrote:
>>> Hi George,
>>>
>>> Judging from the docs, Jonnie looks like a useful package that fills a 
>>> need.
>>> A few questions ...
>>>
>>> Why would someone want to set the TestCorruption flag?
>> It's a built-in self test mechanism. I thought that if the whole point 
>> was to catch read-errors, I should have some way of assuring myself they 
>> would actually be caught.
>>
>>> Do all the files (and all the blocks for that matter) have different
>>> data?  That is, are they all written from a single RNG with a long
>>> period?  That way if a bad driver reads the wrong block, Jonnie can
>>> detect it.
>> The files for sequential and random IO each have different random blocks 
>> of data, but within a file the block is the same. To make every block 
>> random would require essentially a second file that I would have to 
>> write both the blocks to and then read and compare each other against.
>>
>>> Is it possible to use Jonnie against an existing file?  Suppose we have
>>> a huge DBMS that is giving us odd errors.  Could we take the DB down some
>>> night and use Jonnie to read, change, read-verify, restore, read-verify 
>>> blocks?
>> That's an interesting idea that I never thought of. I think that if 
>> you're running a RAID controller, there should not be any media errors. 
>> It would seem to me that any kind of errors would be systematic and not 
>> positional.
>>
>> It wouldn't be a great deal of effort to adjust the code to look for a 
>> test file name to use, but again, with a RAID system I would think any 
>> errors would be systematic.
>>
>>> Thanks!
>>>
>>> Steve
>>>
>>> On Wed, Jan 02, 2008 at 11:35:03AM -0700, George Sexton wrote:
>>>> If you follow the list, you've seen my recent comments about the 
>>>> inadequacy of commonly used disk testing software.
>>>>
>>>> To meet my own needs in this area, I've created my own disk test 
>>>> software tentatively named (wait for it): "jonnie".
>>>>
>>>> If there is sufficient interest, I'll GPL the software and throw it up 
>>>> on Source Forge.
>>>>
>>>> Here's a link to the documentation:
>>>>
>>>> http://www.mhsoftware.com/jonnie/
>>>>
>>>> and a link to the actual application (42KB)
>>>>
>>>> http://www.mhsoftware.com/jonnie/jonnie_0.9.zip
>>>>
>>>> I would appreciate any feedback you have. In particular, I'm interested 
>>>> in feedback on the documentation and on the quality of the tests.
>>>>
>>>> Things I have in mind for this sw before considering it done are:
>>>>
>>>> * Making it possible to localize messages
>>>> * Perhaps making the Random IO Testing a little more paranoid.
>>>>
>>>>
>>>> -- 
>>>> George Sexton
>>>> MH Software, Inc.
>>>> Voice: +1 303 438 9585
>>>> URL:   http://www.mhsoftware.com/
>>>> _______________________________________________
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>> -- 
>> George Sexton
>> MH Software, Inc.
>> Voice: +1 303 438 9585
>> URL:   http://www.mhsoftware.com/
>> _______________________________________________
>> Web Page:  http://lug.boulder.co.us
>> Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
>> Join us on IRC: lug.boulder.co.us port=6667 channel=#colug
> 

-- 
George Sexton
MH Software, Inc.
Voice: +1 303 438 9585
URL:   http://www.mhsoftware.com/