Re: Difference between Vinum and atacontrol RAID?
Pete wrote: [ ... ] The RAID-1 volume I'm using right now is with two drives attached to a non-RAID card with a Promise chipset. Does it work if you move the two drives to another machine without a Promise, Highpoint, or other RAID controller card or MB chipset...? Hardware based RAID is likely to be faster, particularly in the case of parity calculations for RAID-5. (Not that many IDE controllers can do RAID-5, but...) It would be, but the RAID on the Promise and Highpoint devices is not true hardware RAID. It's just software RAID with the drivers moved over to an EPROM on the card. When you write to a RAID-1 mirror on such a device, does the CPU and PCI bus see two copies of the data? Or does the Promise or HPT deal with distributing the data across the right devices itself? > I know from my own experience and that of other people that the Linux software RAID outperforms the "hardware" RAID of these devices. I'm willing to bet that the FreeBSD RAID at least comes close, if not betters the Linux performance. Software-based RAID can do fine for things like -0 & -1; but without numbers, subjective discussion of performance can be misleading -Chuck To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
Re: Difference between Vinum and atacontrol RAID?
On Sun, 09 Mar 2003, Chuck Swiger wrote: > The ATA RAID support via atacontrol apparently requires hardware RAID > controllers like the Promise or Highpoint devices. I don't think this is right. The RAID-1 volume I'm using right now is with two drives attached to a non-RAID card with a Promise chipset. I also get the impression -- though can't test it right now -- that the atacrontrol-based RAID will work across cards. Anyone know for sure about this? > Hardware based RAID is likely to be faster, particularly in the case > of parity calculations for RAID-5. (Not that many IDE controllers can > do RAID-5, but...) It would be, but the RAID on the Promise and Highpoint devices is not true hardware RAID. It's just software RAID with the drivers moved over to an EPROM on the card. I know from my own experience and that of other people that the Linux software RAID outperforms the "hardware" RAID of these devices. I'm willing to bet that the FreeBSD RAID at least comes close, if not betters the Linux performance. Thanks, pete To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
Vinum root file systems (was: Difference between Vinum and atacontrol RAID?)
On Sunday, 9 March 2003 at 20:15:32 -0500, Chuck Swiger wrote: > Pete wrote: > > Generally, one cannot boot from a vinum based-device, unless you are > only doing RAID-1 mirroring. You can have a Vinum root file system as long as at least one plex is concatenated from a single subdisk. > I'm familar with something called "encapsulating the root partition" > under Solaris and Veritas; it's not for the faint-of-heart. :-) I suspect this is the same thing. Greg -- When replying to this message, please copy the original recipients. If you don't, I may ignore the reply or reply to the original recipients. For more information, see http://www.lemis.com/questions.html See complete headers for address and phone numbers pgp0.pgp Description: PGP signature
Re: Difference between Vinum and atacontrol RAID?
Pete wrote: [ ... ] I thought Vinum was FreeBSD's RAID system. If you wanted to do software RAID with FreeBSD, you needed to use Vinum. Now I find this out. Does that ATA subsystem have RAID support built in? (Since atacontrol just seems to control the ATA devices...) If this is so, what's the use of Vinum? When should I use one vs the other? How do Vinum and the ATA subsystem's RAID relate? Vinum resembles a popular commercial RAID product called Veritas LVM; vinum does software-based RAID. The ATA RAID support via atacontrol apparently requires hardware RAID controllers like the Promise or Highpoint devices. Hardware based RAID is likely to be faster, particularly in the case of parity calculations for RAID-5. (Not that many IDE controllers can do RAID-5, but...) The RAID volumes created with vinum are accessible only under FreeBSD, whereas the ATA-based RAID solutions create a logical volume accessible via the normal BIOS interfaces, so the RAID device looks like a single, bigger physical disk drive. Thus you can use an ATA-based hardware RAID volume as a boot device, install multiple operating systems, etc. Generally, one cannot boot from a vinum based-device, unless you are only doing RAID-1 mirroring. I'm familar with something called "encapsulating the root partition" under Solaris and Veritas; it's not for the faint-of-heart. :-) -Chuck To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
Difference between Vinum and atacontrol RAID?
A couple days ago, I asked on the -hackers list about a problem I was having with Vinum and my Promise-based controllers. Søren replied with how to do this by using atacontrol to build the volume. No Vinum seems to be required. I thought Vinum was FreeBSD's RAID system. If you wanted to do software RAID with FreeBSD, you needed to use Vinum. Now I find this out. Does that ATA subsystem have RAID support built in? (Since atacontrol just seems to control the ATA devices...) If this is so, what's the use of Vinum? When should I use one vs the other? How do Vinum and the ATA subsystem's RAID relate? Thanks, pete To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
