4 Operator

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2.8K Posts

February 14th, 2008 02:00

Good morning all.
This is my first question on the forum, so be gentle
with me ;-)


Hi Ben .. :D .. Usually we try to be gentle and polite .. Unless you forget to mark usefull replies ;-)

Given that it's a DMX-3 the track size is 64KB I
think that at 10:14:58 this device had
130304KB WP data in cache which I calculated like
this :-
2036 x 64 = 130304KB


I have to correct you .. even if in a gentle way ;-) It's right to assume that 1 track = 64 kb only if looking at the binfile of your beloved DMX3. But when you use symcli commands, you have another "variable" to play with .. In the /var/symapi/config/options file there is an option you can enable or disable, at your taste :D

SYMAPI_TRACK_SIZE_32K_COMPATIBLE

Remember that by default (since the option is enabled) Solution Enabler will translate DMX3 (and DMX4) 64kb tracks into 32kb tracks. Did you notice that the WP counter is always heavenly even ?? :D

I also have in the back of my mind that I've read
that a volume in the DMX has 4% of its size assigned
in cache for WP which if correct means that my 5GB
volume has around 200MB ringfenced in cache, after
which writes may be held while data is flushed to
disk.


WP is only half of the equation. The 4% of reserved cache is used for both reads and writes. The box may destage tracks from cache (lowering the WP count) for a lot of different reasons (tracks still in cache after a "long" time, read misses that need space in cache) .. So it's hard to fill the reserved cache with writes. This may happen during a recover (hmm restore if you don't love Networker). I'm not 100% sure but if my memory isn't failing, every volume have 4% of its capacity always reserved in cache .. but may "gain" more tracks in cache, if needed.

Have I been gentle enough ?? :D

Cheers !!

15 Posts

February 14th, 2008 03:00

Thanks Stefano. Thats just what I was after.

On checking the variable you mentioned in /var/symapi/config/options it says it is enabled :-
#SYMAPI_TRACK_SIZE_32K_COMPATIBLE = ENABLE

So, with that in mind should my calculations look like this ? :-

At 10:14:58 this device had 65152KB WP data in cache calculated as follows :-
2036 x 32 = 65152KB

Or 63.62MB
65152 / 1024 = 63.62MB

Cheers !

4 Operator

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2.8K Posts

February 14th, 2008 03:00

At 10:14:58 this device had 65152KB WP data in cache
calculated as follows :-
2036 x 32 = 65152KB


It looks good to me :D

-s-

4 Operator

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5.7K Posts

February 14th, 2008 03:00

I vote for some points for the poor Italian man. He sure needs them so his employer can reward him with a new dining room table or something.

9 Legend

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20.4K Posts

February 14th, 2008 03:00

beggars can't be choosers ..you are getting a table man, end of story.

4 Operator

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2.8K Posts

February 14th, 2008 03:00

He sure needs them so his employer can reward him with a
new dining room table or something.


Whooosp Rob .. I forgot to tell you that my home theatre is in perfect working conditions .. Eventually I need a 60' LCD .. can you do something for me ?? :D

Errr.. I don't need a table .. my 300cm table is still good .. Don't need to change it soon :D

4 Operator

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5.7K Posts

February 14th, 2008 03:00

it was an example, you Ingannare ;)

4 Operator

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2.8K Posts

February 14th, 2008 03:00

Oh Rob .. ThX for your support .. Do you prefer a Ford Galaxy or a Citroen C4 Gran Picasso ?? The C4 is already available to me .. If I want the Galaxy I need a lot more points !! ;-)

15 Posts

February 14th, 2008 04:00

Thanks for the help guys, I think I'm getting the hang of this forum.

If I understand correctly, the amount of write pending tracks on our DMX is directly proportionate to the amount of wooden home furnishings, home cinema equipment & people carriers/MPV's that this fine chap recieves in his bonus ?

Sounds like a good deal to me ;-) I'll tell our guys to start hammering that Sym.

Cheers
Ben

4 Operator

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5.7K Posts

February 14th, 2008 04:00

Right on ! And a very small one too ;) One that can barely fit a glas of whine ;)

4 Operator

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5.7K Posts

February 14th, 2008 04:00

Speaking of far, far away: you're up early ! It's now like 8AM or so over there ?

4 Operator

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5.7K Posts

February 14th, 2008 04:00

He's far, far away, remember ? when we wake up, he just went to bed and when he shifts into gear, we're already half way the day.... ;)

9 Legend

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20.4K Posts

February 14th, 2008 04:00

wine ? ..they don't have wine in Italy .it's all imported from California ;)

9 Legend

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20.4K Posts

February 14th, 2008 04:00

i am working since 6:30am ..don't have to drive to the office today, i am telecommuting today. My boss "potentially" gets more work out of me, but i am happy that i don't have to seat in traffic :)

4 Operator

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5.7K Posts

February 14th, 2008 04:00

If I understand correctly, the amount of write pending tracks on our DMX is directly proportionate to the amount of wooden home furnishings, home cinema equipment & people carriers/MPV's that this fine chap recieves in his bonus ?


You are correct ;)
We are a big happy family and sometimes you can even get some great answers on the forum ;)
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