raid 1 with two external drives

[chrisvillar]

Hey,

I'm pretty ignorant on storage and computer hardware in general, so
be gentle. I'm trying to figure out how to set up two external
harddrives in a RAID 1 configuration. They are identical Hammer 400 GB
drives connected to the computer with USB2.0. This is a mobile data
taking operation. What I am trying to do is take advantage of both the
redundancy and backup provided by the RAID 1. I want the data mirrored
in real time and then when done, one of the drives will be Fed-Exed
home. The second drive staying where it is until the first drive
arrives home safely and the data is verified intact. The real time
mirroring is because we are generating data at a rate of 1GB/ minute
and could be running conceivably until the harddrive is nearly full.
If we lose a drive in the 390th minute, it would be extremely
inconvenient. Help please

Chris

 

[Eric Gisin]

Forget USB2, it is slow and high CPU. Windows cannot create dynamic USB disks.

Get a SATA card with external ports and RAID 0/1 support.
Alternatively, a two removable bay FireWire enclosure with RAID.

 

[Arno Wagner]

Hey,

I'm pretty ignorant on storage and computer hardware in general, so
be gentle. I'm trying to figure out how to set up two external
harddrives in a RAID 1 configuration. They are identical Hammer 400 GB
drives connected to the computer with USB2.0. This is a mobile data
taking operation. What I am trying to do is take advantage of both the
redundancy and backup provided by the RAID 1. I want the data mirrored
in real time and then when done, one of the drives will be Fed-Exed
home. The second drive staying where it is until the first drive
arrives home safely and the data is verified intact. The real time
mirroring is because we are generating data at a rate of 1GB/ minute
and could be running conceivably until the harddrive is nearly full.
If we lose a drive in the 390th minute, it would be extremely
inconvenient. Help please

I don't think that RAID1 over USB2.0 will be fast enough to allow you
to both mirror and continue to write data at a speed where the
mirroring is faster or as fast than the writing (which you need in
order for this to work).

Get internal drives, external SATA drives or IDE/SATA drives in
hot-swap enclosures. You also need to stop the writes to the RAID1
array and sync the filesystem before removing the second drive.

Alternatively replicate the data before it is written to disk and
send it to independent USB2.0 drives. That could just be fast
enough. Maybe this will need two independent computers.

Side-note: RAID1 does not qualify as back-up. It only provides
redundancy, since all thinks you mess up on one drive will be gone
on the second one too. A backup protects you from that problem.

Arno

 

[Folkert Rienstra]

I don't think that RAID1 over USB2.0 will be fast enough to allow you

to both mirror and continue to write data

at a speed where the mirroring is faster or as fast than
the writing (which you need in order for this to work).

What do you think that RAID1 actually is?

Get internal drives, external SATA drives or IDE/SATA drives in
hot-swap enclosures. You also need to stop the writes to the RAID1
array and sync the filesystem before removing the second drive.

Alternatively replicate the data before it is written to disk and
send it to independent USB2.0 drives.

That is what RAID1 does too.

That could just be fast enough.
Maybe this will need two independent computers.

Clueless. All it needs is two seperate channels.
The real question is whether USB is considered/allowed for RAID.

Side-note: RAID1 does not qualify as back-up. It only provides
redundancy, since all thinks you mess up on one drive will be gone
on the second one too.

A backup protects you from that problem.

Not 'A' backup but several consequtive ones, upto the current.