Previously Al Dykes said:This card looks interesting.
Can this card run two seperate disk file systems or does it have to
run a raid pair?
Has anyone used it?
Arno Wagner said:This looks like the typical FakeRAID card, i.e. software RAID
in the BIOS chip. That means it is actually a pretty ordinary
SATA controller card. If its driver supports it, it should
work fine as ordinary controller.
Previously TH O said:I'm aware of software raid built into the operating system but I
haven't heard of differences between RAID cards (FakeRAID). Could
you please explain this further? What are the negatives and how can
we identify the cards?
A discussion can be found here: http://linux-ata.org/faq-sata-raid.html
I like to dinstinguish FakeRAID and software RAID. To me software
RAID is a feature of the OS and completely accessible to the
user with OS-integrated tools to manage it. Software RAID is not
tied to some controller or even interface technology. Ideally, it
can also be done with partitions.
Hardware RAID, once assembled (initialized), presents itself to the OS
and generally the PC-side of its interface, as one large device.
There will still be some management software, but all the RAID
operations are done on the card. Hardware RAID cards have their own
small computer in them, with some limited degree of autonomity. The
primary advantage is that hardware RAID does typically work without
special drivers and that things like disk replacement can even be
hidden from the OS. The second advantages is that the busses in the
PC do only need to carry the final datastream and the CPU does not
need to do any RAID algorithms.
FakeRAID is software RAID in the BIOS chip of the controller.
This has all the bad sides of hardware RAID, namely controller
failure makes the RAID unacessible and all the bad sides of software
RAID, namely more load on CPU and busses, without the advantages
of either. It also tends to be OS specific. The reason to call it
FakeRAID is that these things are marketed as if they were hardware
RAID, when they are not. IMO, it is a worst possible solution.
Arno
A discussion can be found here: http://linux-ata.org/faq-sata-raid.html
I like to dinstinguish FakeRAID and software RAID. To me software
RAID is a feature of the OS and completely accessible to the
user with OS-integrated tools to manage it. Software RAID is not
tied to some controller or even interface technology. Ideally, it
can also be done with partitions.
Hardware RAID, once assembled (initialized), presents itself to the OS
and generally the PC-side of its interface, as one large device.
There will still be some management software, but all the RAID
operations are done on the card. Hardware RAID cards have their own
small computer in them, with some limited degree of autonomity.
The primary advantage is that hardware RAID does typically work
without special drivers
and that things like disk replacement can even be hidden from the OS.
The second advantages
is that the busses in the PC do only need to carry the final data
stream and the CPU does not need to do any RAID algorithms.
FakeRAID is software RAID in the BIOS chip of the controller.
This has all the bad sides of hardware RAID, namely controller
failure makes the RAID unacessible and all the bad sides of software
RAID, namely more load on CPU
and busses,
without the advantages of either.
It also tends to be OS specific.
The reason to call it FakeRAID is that these things are marketed as
if they were hardware RAID, when they are not.
IMO, it is a worst possible solution.
Arno Wagner said:Previously TH O said:A discussion can be found here: http://linux-ata.org/faq-sata-raid.html
I like to dinstinguish FakeRAID and software RAID. To me software
RAID is a feature of the OS and completely accessible to the
user with OS-integrated tools to manage it. Software RAID is not
tied to some controller or even interface technology. Ideally, it
can also be done with partitions.
Hardware RAID, once assembled (initialized), presents itself to the OS
and generally the PC-side of its interface, as one large device.
There will still be some management software, but all the RAID
operations are done on the card. Hardware RAID cards have their own
small computer in them, with some limited degree of autonomity. The
primary advantage is that hardware RAID does typically work without
special drivers and that things like disk replacement can even be
hidden from the OS. The second advantages is that the busses in the
PC do only need to carry the final datastream and the CPU does not
need to do any RAID algorithms.
FakeRAID is software RAID in the BIOS chip of the controller.
This has all the bad sides of hardware RAID, namely controller
failure makes the RAID unacessible and all the bad sides of software
RAID, namely more load on CPU and busses, without the advantages
of either. It also tends to be OS specific. The reason to call it
FakeRAID is that these things are marketed as if they were hardware
RAID, when they are not. IMO, it is a worst possible solution.
Arno
Arno, thanks for the lengthy explanation ... it was very informative.
Arno Wagner said:Arno, thanks for the lengthy explanation ... it was very informative.
Some people just soo utterly deserve the clueless babblebot.
Previously TH O said:Arno, thanks for the lengthy explanation ... it was very informative.
No problem.
Arno