acid_kewpie did in post 4. Yeah, he didn't say I had to use LVM. But maybe he was saying that was the only way to do 3+-way mirroring. I do remember long ago using the MD RAID and trying to set that up and it didn't have a way to specify 3 drives for a mirror. Maybe it does, now.

I know there are other ways. I've never tried the LVM way. I don't want to, either. I like to keep life simple. A simple means to create new block devices (partitionable) from multiple other data sources is all that should be needed. Ideally, they should have integrated this with loopback devices in a more generic way, such that you have the kernel create a block device out of whatever sources you reference (other block devices including individual partitions, files, and even network block device sources).


Hmm. No. No. I only mentioned LVM to head off more suggestions to use LVM.

I have avoided it due to performance issues. Those issues were not the software implementation, but rather, were hardware issues due to the RAID being done in software.

If your controller slows down, or the drivers for it slow down, due to multiple device I/O, the software RAID can be a loser. Older controllers would readily do that, especially the cheap chip controllers used on most motherboards. Even most high-end server boards had these with the idea that if this was for a machine that needed RAID I/O performance, you'd add that. Before SATA, few, if any, motherboards even had SCSI on board ... you added that in one or more controller cards. And even then, SCSI would hurt performance unless you split things across multiple SCSI channels. Most motherboards had IDE on the board, and performance usually was bad for anything more than one device (even if there were 2 IDE channels). Some of the IDE issues were driver issues, too.

SATA came along, and as it matured, these issues have become mostly moot. Now, everyone is doing one device per SATA channel (you can do more, but it's harder to implement ... and I'm glad it has not caught on). Many, probably most now, SATA controllers can do all I/O channels pretty much independently.

Still, software RAID 1 does consume some extra RAM buffer space.

Software RAID is more practical now than it was before. I really should get back into it. But I'm also often finding that I need more than the 6 SATA channels the motherboard has. Anyone know of a high performance SATA/PCIe controller that does NOT do RAID (e.g. is cheaper than a RAID card)?

Please read my posts more carefully
I told you I never heard the above quoted statement you made about duplicated buffers in linux software RAID drivers, and asked for links about it, not LVM.
I know what LVM is

I also did not understand the quoted statement, so asked for you to clarify.

Also, once again, I never heard of this...

You can do all of this with linux software RAID.

Something is wrong with the threading in this thread. This is not what I read. Now the posts seem to be out of order. The quoting is even inconsistent. So it seems what displayed for me and what displayed for you are not the same. But I have not been keeping snapshots of it, so I cannot go back. I'm outa here, now.

@Slax-Dude: I have edited post #15. Please, check if it appears as the original one, now. Thanks.

It does
Thank you so much for fixing it!