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Home > Archive > Data Storage > June 2005 > SATA II with external enclosure?
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SATA II with external enclosure?
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| I'm looking for an external HDD that I can use for backing up my desktop.
I'm thinking about going with an external SATA II drive/enclosure. That way
I can upgrade to a bigger disk as needed, and I'd get 3Gps throughput. I'm
relatively new to SATA and hope I can field some questions here...
* Because the external HDD is for backup, I'm worried that if my OS (WinXP)
becomes corrupted, somehow a bit will get flipped on the external drive, or
the MBR of the drive could get messed up - preventing access to my data even
after I reinstall my OS - and bye-bye backup. Is this a valid concern? An
external USB drive, on the other hand, (although slower) is more independent
from the OS and would be less likely to get messed up after an OS
corruption - is this correct?
* Would an external SATA drive be hot-swappable between computers? I would
be using an external SATA port adapter
http://www.cooldrives.com/dual-port...r-sata-ii-.html
that essentially extends the SATA II port on the motherboard to the back of
the case - is it safe to plug/unplug this like a USB port?
* Would I get 3Gps throughput? I've heard that this is only possible with a
PCI-X SATA card. Is this true? Shouldn't the SATA II controller on the
motherboard provide this throughput?
Thanks in advance!
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| Ron Reaugh 2005-06-23, 2:46 am |
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"deko" <deko@deko.com> wrote in message
news:%Wmue.32041$J12.26660@newssvr14.news.prodigy.com...
> I'm looking for an external HDD that I can use for backing up my desktop.
> I'm thinking about going with an external SATA II drive/enclosure. That
way
> I can upgrade to a bigger disk as needed, and I'd get 3Gps throughput.
Nope, that's the peak burst rate of the interface and not the speed of the
drive. Around 50MB/sec. is tops for today's drives.
I'm
> relatively new to SATA and hope I can field some questions here...
>
> * Because the external HDD is for backup, I'm worried that if my OS
(WinXP)
> becomes corrupted, somehow a bit will get flipped on the external drive,
or
> the MBR of the drive could get messed up - preventing access to my data
even
> after I reinstall my OS - and bye-bye backup. Is this a valid concern?
Yes but obscure. The drive could also be hit by a meteroid.
An
> external USB drive, on the other hand, (although slower) is more
independent
> from the OS and would be less likely to get messed up after an OS
> corruption - is this correct?
NO, the same applies either way.
> * Would an external SATA drive be hot-swappable between computers? I
would
> be using an external SATA port adapter
> http://www.cooldrives.com/dual-port...r-sata-ii-.html
> that essentially extends the SATA II port on the motherboard to the back
of
> the case - is it safe to plug/unplug this like a USB port?
HW wise it's safe. The OS and driver software is a different issue and the
answer there varies.
> * Would I get 3Gps throughput? I've heard that this is only possible with
a
> PCI-X SATA card. Is this true?
Nope, not with any card for sustained transfers.
> Shouldn't the SATA II controller on the
> motherboard provide this throughput?
Generally they do for very short bursts.
| |
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| > > I'm looking for an external HDD that I can use for backing up my
desktop.
> way
>
> Nope, that's the peak burst rate of the interface and not the speed of
the
> drive. Around 50MB/sec. is tops for today's drives.
let's see... if 50MB/sec = 400mbps, then an 8-drive RAID 0 array [8*400 =
3200mbps (or 3.2gbps)] would be needed to max out the capacity of the SATA
II interface - is this correct?
>
> I'm
> (WinXP)
> or
> even
>
> Yes but obscure. The drive could also be hit by a meteroid.
Aghh!! Another thing to plan for...
> An
> independent
>
> NO, the same applies either way.
Perhaps the only way to ameliorate meteoroid risk (and still have decent
throughput) would be to have 2 PCs connected via GigE interfaces with a
crossover cable. Then I'd only have to worry about a scenario where TWO
meteoroids fell - one hitting each PC. Nevertheless, if we entertain a
50MB/sec ceiling for HDD throughput, the gating factor in data transfer
(with a single drive) would be the drive. Furthermore, a USB 2.0 interface
(480mbps) could then be expected perform as well as a GigE interface
(1000mbps) since the HDD can only handle 400mbps. But I've tested that
particular scenario by copying the same 1Gb of data from my PC to an
external USB drive, and between 2 PCs over a GigE link. The results were
that USB 2.0 took roughly twice as long. I'm not sure how to explain this
if the interface was NOT the bottleneck... unless the external USB drive was
significantly slower than the internal HDDs in the PCs.
> would
> of
>
> HW wise it's safe. The OS and driver software is a different issue and
the
> answer there varies.
That makes sense. But the OS and driver can go up in flames as long as my
data remains inviolate. I can always buy a new PC or install a new driver
or OS - but I can't replace my data.
with[vbcol=seagreen]
> a
>
>
> Nope, not with any card for sustained transfers.
10-4.
>
> Generally they do for very short bursts.
>
>
Thanks for the reply.
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| Ron Reaugh 2005-06-23, 7:47 am |
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"deko" <deko@deko.com> wrote in message
news:bCuue.2953$Bx6.1136@newssvr13.news.prodigy.com...
> desktop.
That[vbcol=seagreen]
> the
>
> let's see... if 50MB/sec = 400mbps, then an 8-drive RAID 0 array [8*400 =
> 3200mbps (or 3.2gbps)] would be needed to max out the capacity of the SATA
> II interface - is this correct?
Nope, SATA is not like SCSI. Each SATA II drive is on a separate channel.
drive,[vbcol=seagreen]
data[vbcol=seagreen]
concern?[vbcol=seagreen]
>
> Aghh!! Another thing to plan for...
>
>
> Perhaps the only way to ameliorate meteoroid risk (and still have decent
> throughput) would be to have 2 PCs connected via GigE interfaces with a
> crossover cable.
On different continents in granite mines.
> Then I'd only have to worry about a scenario where TWO
> meteoroids fell - one hitting each PC. Nevertheless, if we entertain a
> 50MB/sec ceiling for HDD throughput, the gating factor in data transfer
> (with a single drive) would be the drive. Furthermore, a USB 2.0
interface
> (480mbps) could then be expected perform as well as a GigE interface
> (1000mbps) since the HDD can only handle 400mbps.
Both are peak theotetical rates and actual sustained throughput may not get
there.
> But I've tested that
> particular scenario by copying the same 1Gb of data from my PC to an
> external USB drive, and between 2 PCs over a GigE link. The results were
> that USB 2.0 took roughly twice as long.
HUH, what took twice as long as what exactly?
> I'm not sure how to explain this
> if the interface was NOT the bottleneck... unless the external USB drive
was
> significantly slower than the internal HDDs in the PCs.
That may be the case. Use external SATA II.
>
http://www.cooldrives.com/dual-port...r-sata-ii-.html[vbcol=seagreen]
back[vbcol=seagreen]
> the
>
> That makes sense. But the OS and driver can go up in flames as long as my
> data remains inviolate. I can always buy a new PC or install a new driver
> or OS - but I can't replace my data.
>
> with
>
> 10-4.
>
>
> Thanks for the reply.
>
>
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| > > > > I'm looking for an external HDD that I can use for backing up my
> That
throughput.[vbcol=seagreen]
of[vbcol=seagreen]
=[vbcol=seagreen]
SATA[vbcol=seagreen]
>
> Nope, SATA is not like SCSI. Each SATA II drive is on a separate
channel.
Does this mean the SATA interface is WAY faster than currently available
SATA drives? I've heard reports that a SATA II drive on a SATA II interface
will provide a 7 to 15% increase in throughput over a SATA I drive on a SATA
I interface (all other things being equal). This is far short of the
theoretical speed increase of SATA I over SATA II.
> drive,
> data
> concern?
>
> On different continents in granite mines.
>
> interface
>
> Both are peak theotetical rates and actual sustained throughput may not
get
> there.
>
were[vbcol=seagreen]
>
> HUH, what took twice as long as what exactly?
Copying 1Gb of data from my PC to an external USB drive took twice as long
as copying the same 1Gb of data from my PC to another PC over a GigE link.
> was
>
> That may be the case. Use external SATA II.
External SATA sounds like the best backup solution - at least for backing up
data. You could have a script run each night and backup all your data, and
even maintain rolling "snapshots" of directories replicated each week (if
you had enough disk space). For backing up your OS/Apps, the way to go
would be use a separate System disk and clone it periodically with something
like this: http://www.logicube.com/products/hd...cation/echo.asp
I[vbcol=seagreen]
> http://www.cooldrives.com/dual-port...r-sata-ii-.html
> back
and[vbcol=seagreen]
my[vbcol=seagreen]
driver[vbcol=seagreen]
possible[vbcol=seagreen]
>
>
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| Ron Reaugh 2005-06-23, 7:47 am |
|
"deko" <deko@deko.com> wrote in message
news:c%vue.2961$Bx6.479@newssvr13.news.prodigy.com...
> Does this mean the SATA interface is WAY faster than currently available
> SATA drives?
Yep.
> I've heard reports that a SATA II drive on a SATA II interface
> will provide a 7 to 15% increase in throughput over a SATA I drive on a
SATA
Well any SATA[II] drive that is 7-15% faster than another SATA[II] drive
will remain that 7-15% faster regardless on which drive is on which
interface SATA vs SATAII.
> I interface (all other things being equal). This is far short of the
> theoretical speed increase of SATA I over SATA II.
Right, the interface has nothing to do with it except that the interface
should be faster. Drive speed is primarily determined by the number of user
sectors per track & RPM AND the average access time.
> Copying 1Gb of data from my PC to an external USB drive took twice as long
> as copying the same 1Gb of data from my PC to another PC over a GigE link.
That bears some further research.
> External SATA sounds like the best backup solution - at least for backing
up
> data. You could have a script run each night and backup all your data,
and
> even maintain rolling "snapshots" of directories replicated each week (if
> you had enough disk space). For backing up your OS/Apps, the way to go
> would be use a separate System disk and clone it periodically with
something
> like this: http://www.logicube.com/products/hd...cation/echo.asp
Well the best way is to make a compressed image of the whole drive using
something like Acronis's TrueImage.
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