Question: Real-Time Back-up

  • Thread starter Thread starter Darren Harris
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Darren Harris

Can anyone explain why after all this time there is no easy,
inexpensive, and reliable way to get all data to write to two or more
identically sized hard drives in a system *at exactly the same time*?

It is obvious that if there is a mechanical failure, this is the only
way that one will still have a back-up drive that is *exactly* the
same down to every last bit as the drive that went down.

Thanks a lot.

Darren Harris
Staten Island, New York.
 
Darren Harris said:
Can anyone explain why after all this time there is no easy,
inexpensive, and reliable way to get all data to write to two or more
identically sized hard drives in a system *at exactly the same time*?

It is obvious that if there is a mechanical failure, this is the only
way that one will still have a back-up drive that is *exactly* the
same down to every last bit as the drive that went down.
Click to expand...


Isn't that what RAID 1 does?

Jim
 
Darren said:
Can anyone explain why after all this time there is no easy,
inexpensive, and reliable way to get all data to write to two or more
identically sized hard drives in a system *at exactly the same time*?

It is obvious that if there is a mechanical failure, this is the only
way that one will still have a back-up drive that is *exactly* the
same down to every last bit as the drive that went down.

Thanks a lot.

Darren Harris
Staten Island, New York.
Click to expand...

Um, RAID?
 
Um, RAID?
Click to expand...

I suppose RAID 1 or 5 is the closest to that. Don't know that the bits are
exactly the same during the failure, but during recovery you can mirror the
good drive. I'm not too up on RAID 1 though, I'm usually going for RAID 0,
speed :-).

You can verify the contents of the drives with md5sum or some other hash.

Michael
 
The guy said "Um, RAID?" which I take to mean he doesn't know what RAID is.

RAID stands for Redundant Array of Inexpensive (or Independent) Drives. I
know hardly anything about the mechanics of RAID but one of the
possibilities is to parallel them to get simultaneous writing to borh
drives.

Bearman
 
Can anyone explain why after all this time there is no easy,
inexpensive, and reliable way to get all data to write to two or more
identically sized hard drives in a system *at exactly the same time*?

It is obvious that if there is a mechanical failure, this is the only
way that one will still have a back-up drive that is *exactly* the
same down to every last bit as the drive that went down.
Click to expand...

It's called RAID, you can get a cheapo hardware RAID card for under $50,
or software RAID for free with most modern operating systems.
 
Can anyone explain why after all this time there is no easy,
inexpensive, and reliable way to get all data to write to two or more
identically sized hard drives in a system *at exactly the same time*?

It is obvious that if there is a mechanical failure, this is the only
way that one will still have a back-up drive that is *exactly* the
same down to every last bit as the drive that went down.
Click to expand...

RAID1 - Hit the www.promise.com or www.3ware.com
websites for info on the PCI RAID cards that hook up to
either (2) PATA or (2) SATA disks.

Advantages:
- single drive failure is handled invisibly, until the
2nd drive fails (make sure to replace failed drives ASAP
or have a hot spare available)

Disadvantages:
- more complicated to install, requires seperate drivers
during installation
- often slower then a non-RAID system
- every byte of storage costs twice as much
- doesn't protect against accidental deletions or
corruption of files on the file system

Sometimes it's better to run a single disk, using Ghost
periodically as well as a data mirroring program like
Second Copy to protect the data to a second drive.
Ghosting allows you to snapshot the O/S so you can go
back to a fixed point in time when everything was
working. Second Copy handles keeping a backup copy of
your data files (along with past revisions, or deleted
files) on the 2nd drive.
 
I assumed that RAID was reliable. But going by the responses here, it
is the common consensus that RAID has become easy and inexpensive
also, correct?

Thanks.

Darren Harris
Staten Island, New York.
********************************************************************************
 
Darren Harris said:
I assumed that RAID was reliable. But going by the responses here, it
is the common consensus that RAID has become easy and inexpensive
also, correct?

Thanks.

Darren Harris
Staten Island, New York.
****************************************************************************
****


RAID1 - Hit the www.promise.com or www.3ware.com
websites for info on the PCI RAID cards that hook up to
either (2) PATA or (2) SATA disks.

Advantages:
- single drive failure is handled invisibly, until the
2nd drive fails (make sure to replace failed drives ASAP
or have a hot spare available)

Disadvantages:
- more complicated to install, requires seperate drivers
during installation
- often slower then a non-RAID system
- every byte of storage costs twice as much
- doesn't protect against accidental deletions or
corruption of files on the file system

Sometimes it's better to run a single disk, using Ghost
periodically as well as a data mirroring program like
Second Copy to protect the data to a second drive.
Ghosting allows you to snapshot the O/S so you can go
back to a fixed point in time when everything was
working. Second Copy handles keeping a backup copy of
your data files (along with past revisions, or deleted
files) on the 2nd drive.
Click to expand...
[/QUOTE]
Pretty much yes, alot of MOBO's come with a built in Raid option for the
IDE controllers which means you only have to supply the additional drives.
f you don't have this option a raid card is fairly inexpensive now too.
 
Pretty much yes, alot of MOBO's come with a built in Raid option for the
IDE controllers which means you only have to supply the additional drives.
f you don't have this option a raid card is fairly inexpensive now too.
Click to expand...

HOWEVER, the RAID options in most current consumer-grade computers are
SATA-based, offering RAID 0 (striping = performance) or RAID 1 (mirroring = data
safety), and are limited to 2 HDs in the array. While they do give you a good
set of options, they will not give the combination of performance and data
safety of a server-grade, hot-pluggable, RAID 5 (striping + CRC for data
recovery) array. The RAID 5 array is usually SCSI based and needs a minimum of
3 HDs.

There may be EIDE/ATA based RAID controllers available, but I don't think they
are considered "mainstream" yet, as are the embedded SATA RAID 0/1 controllers.
 
There may be EIDE/ATA based RAID controllers available, but I don't think they
are considered "mainstream" yet, as are the embedded SATA RAID 0/1 controllers.
Click to expand...


Huh?

Most if not all the major manufacturers have released boards with onboard
ATA RAID controllers, but they were separate chips like Promise,
Highpoint, Silicon Image. They've been around for several years, perhaps
gaining popularity in the past 2-3 years because of a lower price
differential between those boards having the controller and (essentially
same model) board without.
 
There may be EIDE/ATA based RAID controllers available, but I don't think they
are considered "mainstream" yet, as are the embedded SATA RAID 0/1 controllers.
Click to expand...

SATA RAID is less mainstream than the EIDE/ATA RAID motherboards. SATA is
gaining ground, but I think I will stick IDE based boards.

I have had one, ATA/EIDE RAID for what 3+ years. Long before SATA was around.
 
kony said:
Most if not all the major manufacturers have released boards with onboard
ATA RAID controllers, but they were separate chips like Promise,
Highpoint, Silicon Image. They've been around for several years, perhaps
gaining popularity in the past 2-3 years
Click to expand...

OK. I have yet to see any ATA RAID controllers or setups advertised by
mainstream mfgrs like Dell -- even in their "performance" home machines...
 
OK. I have yet to see any ATA RAID controllers or setups advertised by
mainstream mfgrs like Dell -- even in their "performance" home machines...
Click to expand...

Look at the RAID offerings for the low end Dell servers like the 400sc
line. Ide raid controllers. Some of them Promise, some unnamed
manufacturer. Targeted at the small business server market. They have
offered IDE RAID for a couple years.

Also look at the raid controllers from Adaptec and 3ware. This is not
counting the SATA raid that is starting to hit the market

JT
 
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