[dba-Tech] why oh why - big copy bursts

If you can't find a place for them in another system, there's always the option of buying external usb drive enclosures and using them as backup drives.  Maybe you have client that could use them on their system(s)?

----- Original Message ----
From: jwcolby <jwcolby at colbyconsulting.com>
To: Discussion of Hardware and Software issues <dba-tech at databaseadvisors.com>
Sent: Friday, February 8, 2008 11:21:24 AM
Subject: [dba-Tech] why oh why - big copy bursts


I 
am 
trying 
to 
copy 
a 
30 
gig 
file 
from 
one 
computer 
to 
another.  
Task
Manager 
shows 
it 
"bursting" 
transmission 
at 
30-40% 
of 
network 
bandwidth 
for
10 
or 
20 
seconds 
and 
then 
transferring 
at 
3% 
or 
so 
for 
10 
minutes 
or 
so.
While 
it 
is 
bursting 
it 
shows 
"will 
complete 
in 
10 
minutes", 
when 
it 
trails
off 
it 
shows 
"will 
complete 
in 
160 
minutes".  
Obviously 
I 
want 
this 
thing 
to
finish 
so 
I 
can 
copy 
the 
next 
file.

Any 
idea 
why 
I 
would 
be 
seeing 
something 
like 
this?

Actually 
I 
just 
took 
a 
bathroom 
break 
and 
while 
thinking 
about 
it 
I 
may 
have
come 
up 
with 
the 
answer.  
Software 
raid 
0.  
The 
destination 
disk 
is 
a
software 
raid 
0 
drive 
using 
three 
different 
drives.  
Perhaps 
the 
destination
computer 
is 
caching 
a 
bunch 
of 
data 
and 
then 
runs 
out 
of 
room 
to 
cache 
more
while 
it 
writes 
the 
data 
out 
to 
the 
Raid1 
volume.  
Which 
would 
answer 
the
question 
of 
why 
I 
would 
choose 
JBOD 
over 
RAID0.  
The 
write 
calculations
required 
to 
do 
RAID0.

On 
a 
related 
note, 
I 
decided 
to 
test 
this 
theory.  
I 
shut 
off 
the 
computer
and 
started 
fiddling 
with 
the 
drives.  
I 
decided 
to 
just 
move 
the 
drives 
out
of 
my 
WHS 
box 
and 
place 
them 
in 
my 
SQL 
Server 
box 
and 
ran 
square 
up 
against
my 
power 
supply.  
I 
have 
a 
700 
watt 
supply 
in 
there 
but 
when 
I 
added 
the
three 
drives 
into 
that 
box 
the 
system 
would 
turn 
on, 
then 
right 
back 
off.
When 
I 
disconnected 
the 
new 
drives 
the 
computer 
turned 
on 
just 
fine.  
These
are 
old 
western 
digital 
caviar 
250 
gig 
drives, 
the 
kind 
that 
came 
out 
when
the 
SATA 
drives 
were 
just 
entering 
the 
market, 
with 
a 
normal 
power 
connector
and 
a 
SATA 
connector.  
Anyway, 
my 
700 
watt 
supply 
just 
wouldn't 
handle 
the
load.

Sigh.

I 
now 
have 
4 
of 
these 
old 
WD 
drives 
just 
sitting 
there.  
A 
terabyte 
of
identical 
drives 
and 
no 
home 
for 
them.  
I 
guess 
I 
will 
tear 
open 
one 
of 
my
other 
boxes 
and 
see 
if 
I 
can 
get 
them 
mounted 
in 
some 
other 
system.

John 
W. 
Colby
Colby 
Consulting
www.ColbyConsulting.com 

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