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February 14th, 2008 02:00

Symstat WP question - SYMCLI Version V6.2.1.0

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

I don't have a support problem to solve, I'm just using symstat to gather some info & then trying to make sure I understand the results.

What I have is a DMX-3 1500 & the volume I'm looking at is a a 5GB volume (0278) which is a Windows 2K3 boot lun.

This server has just been deployed so the Windows guys are no doubt copying zip files around & installing software etc so I thought I'd run symstat to see how it looked. I've pasted the symstat output at the end of this post.

Now here's the bit where I need you guys to check my logic if you don't mind ?

The highest number of write pending tracks in the output is at 10:14:58 where it hits 2036 in the WP column.

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

Or around 127.25MB
130304 / 1024 = 127.25MB

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.

It would be great if someone had a second to sense check my logic here & give me any insight as to whether I'm on target with my reasoning ?

# symstat -dev 0278 -i 5
DEVICE IO/sec KB/sec % Hits %Seq Num WP
10:14:05 READ WRITE READ WRITE RD WRT READ Tracks
10:14:10 0278 (Not Visible ) 72 184 845 1367 75 100 0 732
10:14:16 0278 (Not Visible ) 31 224 328 2120 81 100 0 1020
10:14:21 0278 (Not Visible ) 14 74 275 728 50 100 0 1136
10:14:26 0278 (Not Visible ) 28 86 493 673 68 100 0 1190
10:14:32 0278 (Not Visible ) 1 23 16 271 0 100 0 1188
10:14:37 0278 (Not Visible ) 1 11 23 89 0 100 0 1096
10:14:42 0278 (Not Visible ) 22 310 346 1827 73 100 0 1084
10:14:48 0278 (Not Visible ) 4 72 127 2685 100 100 0 1408
10:14:53 0278 (Not Visible ) 30 148 510 3100 63 100 0 1814
10:14:58 0278 (Not Visible ) 78 139 584 1885 78 100 0 2036
10:15:04 0278 (Not Visible ) 7 30 112 318 57 100 0 1964
10:15:09 0278 (Not Visible ) 3 73 57 460 33 100 0 1728
10:15:15 0278 (Not Visible ) 54 35 1374 320 31 100 2 1268
10:15:20 0278 (Not Visible ) 0 12 0 76 N/A 100 N/A 1248

Thanks

Ben

6 Operator

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2.8K Posts

February 14th, 2008 04:00

I was asking myself why you didn't yet jump in the crowd :D

Welcome back Dynamox !!

Cheers !!

6 Operator

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2.8K Posts

February 14th, 2008 05:00

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



Ok Ben .. I've got my points .. The Galaxy is a step closer now .. :D

Now you can be sure that we'll be gentle with you ;-)

-s-

6 Operator

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5.7K Posts

February 14th, 2008 05:00

No "useful" points to give away ?

6 Operator

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February 14th, 2008 05:00

Any ideas of which instructor you would have had ? If
you get to do the course anytime in the future and
you're getting Desiree Thisbe, give her my regards ;)
I got the same course in feb 2007.


Desiree !! I met her hmmm 3 to 4 years ago .. :D I think she won't ever remember me .. But I remember her !! :-)

However if my memory doesn't fail, she is based in UK .. hard to believe that US will call her for the Perf Training .. Usually EMEA instructors covers both EMEA (up to saudi arabia) and the whole Africa (that usually means South Africa only) while USA instructors deliver trainings all around US :D

6 Operator

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February 14th, 2008 05:00

c'mon .. don't be shy !!! you have plenty of experiences to share .. :D

I'm sorry for the training .. Unfortunatly EMEA is a different region .. I can't do that much for you :(

Good morning !! Even if you didn't drive today and are sitting in your bed, using your portable PC and enjoing a Coke :-P

11 Legend

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February 14th, 2008 05:00

i don't remember instructor's name, but it was not Desiree. I am going to reschedule class for later on, can you see who's teaching the class when you register ...i don't remember seeing instructor's name.

11 Legend

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February 14th, 2008 05:00

they canceled class due to low enrollment, what's up with that? I would think people would line up to take this class ..i guess it's not the case.

11 Legend

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February 14th, 2008 05:00

I was asking myself why you didn't yet jump in the
crowd :D

Welcome back Dynamox !!

Cheers !!


heheh ;) , when it comes to performance/configuration/architecture questions ...i am sitting back and learning from your and Rob's posts. I have got a long way to go in those areas :) ...and EMC just canceled my "Symmetrix performance workshop" class ..how rude.

11 Legend

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February 14th, 2008 05:00

i am not sure ..maybe start of the year ..people have a lot of projects kicking off, no time to take classes.

6 Operator

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February 14th, 2008 05:00

However the Symm Perf Workshop is a goood course, you won't get exact numbers to look at in real life. It's a matter of gut feeling....

Any ideas of which instructor you would have had ? If you get to do the course anytime in the future and you're getting Desiree Thisbe, give her my regards ;) I got the same course in feb 2007.

6 Operator

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February 14th, 2008 05:00

Maybe the time of year is all wrong ? What is going on over there at this time that would make people ignore this class ? Last year, when I went, there were 12 people there...

6 Operator

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February 14th, 2008 06:00

I've had instructor's that covered the whole world.
Is D based in the UK ? I think she said she was from
Mautitius....


She was born in Mauritius .. But she moved to UK .. I don't really know where in the world is now Desiree :D

I'll send her a mail .. :D

6 Operator

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February 14th, 2008 06:00

I took my class in february as well and, like I said: lots of people there.... no places left.

6 Operator

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5.7K Posts

February 14th, 2008 06:00

I've had instructor's that covered the whole world. Is D based in the UK ? I think she said she was from Mautitius....

6 Operator

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5.7K Posts

February 14th, 2008 06:00

when you register yourself through Powerlink, you can see the instructor's name. Click on details (or whatever it is called and there you go).
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