FAQ:
1)
What
is
degraded
mode?
M52
works
in
degraded
mode
when
one
and
only
one
of
the
healthy
RAID
array
set
of
disks
is
removed.
While
in
degraded
mode,
the
unit
continues
to
operate
without
loss
of
data,
storage
capacity,
or
performance.
However,
the
unit
is
no
longer
secure
and
will
suffer
data
loss
if
one
or
more
disk
fails.
2)
One
of
the
HDD
LED
flashes
blue
for
1
or
2
minute
after
power
up.
What
is
it
doing
and
why?
The
short
‐
time
LED
flash
means
the
corresponding
HDD
is
rebuilding.
It's
because
the
previous
power
off
happens
before
disks
commit
their
caches
to
disk,
which
causes
the
data
or
parity
inconsistency
on
the
disk.
The
short
‐
time
rebuild
upon
power
up
will
correct
the
inconsistency.
3)
Can
I
swap
any
of
the
HDDs
in
the
unit
or
between
units?
No.
Each
disk
has
a
unique
global
ID
which
ensures
that
disks
cannot
be
swapped
between
sets
–
although
sets
with
swapped
disks
might
behave
correctly,
the
data
is
useless
because
it
is
mixed
up.
4)
Why
does
it
take
so
long
to
power
up
the
unit?
The
system
switches
on
the
disks
independently
and
with
sufficient
delay
between
disks
to
minimize
peak
power
consumption
during
motor
spin
‐
up.
5)
Can
other
HDD
brands
been
used
(e.g.
WD
red)?
M52
allows
the
SATA
disk
drives
to
be
of
different
brands
and
sizes.
The
capacity
of
a
set
of
RAID
disks
is
twice
of
the
smallest
disk
size,
leaving
the
upper
part
of
any
larger
disk
unused.
However,
HDDs
of
identical
capacities
and
same
models
are
recommended.
In
case
you
can’t
get
identical
HDDs
for
a
RAID
set,
be
aware
that:
¾
The
smallest
HDD
disk
size
can’t
be
greater
than
1TB
due
to
configuration
¾
When
M52
already
works
in
degraded
mode,
a
new
HDD
plugged
into
the
array
for
rebuild
must
be
at
least
the
size
of
the
smallest
disk
used
when
the
set
of
RAID
disks
was
created
¾
HDD
disk
voltage
tolerance
can’t
be
greater
than
5%
for
+5v
and
10%
for
+12v
¾
If
HDD
disks
are
not
SATA
II
or
SATA
III
type,
the
data
transmission
speed
will
be
decreased
and
the
rebuild
time
will
be
longer
6)
If
the
controller
board
is
replaced
but
the
existing
three
HDDs
are
kept
using,
what
will
happen?
If
the
controller
board
is
configured
same
as
the
one
before
replaced,
i.e.
same
RAID
mode,
disk
number,
and
flash
type/speed
etc.,
and
the
existing
three
HDDs
are
kept
same
position,
the
RAID
set
of
disks
should
work
just
fine
as
the
serial
numbers
of
the
HDDs
all
match
and
they
are
automatically
treated
as
a
complete
set.
Содержание M52
Страница 1: ...NAD SERVICE MANUAL M 52 M 52 Digital Music Vault Digital Music Vault ...
Страница 16: ...keyboard Layout ...
Страница 17: ...DCDC board layout ...
Страница 18: ...SMPS board layout ...