you need to have to raid cards and have it set up so that for a primary and secondary sort of thing where if one drops out the other card takes over and you can then replace the failed card. After that you need to resync. It takes fancy software but we used to do it all the time on Risc 6k boxes. I'm sure there's something equivalent for the mac units.
On Tue, Feb 23, 2010 at 7:48 PM, John Carmonne <[email protected]> wrote: > > On Feb 23, 2010, at 4:26 PM, Bruce Johnson wrote: > > > > > On Feb 23, 2010, at 2:20 PM, Dan wrote: > > > >>> > >>> For Data security at the cost of speed is RAID 5 across 3 disks. There > is a parity bit so that if one drive fails, you still can recover the data > by replacing the failed drive. Slower than RAID 0, but your data is secure. > >> > >> until the RAID card itself dies, and spazzes out on the master blocks. > The replacement card cannot then recover things, so you've lost it all > anyway. > >> > >> Which brings you back to Len's first query. Iffa you do RAID you gots > to keep really good backups or risk loosing EVERYTHING. Big datacenters use > RAID with LOTS of HDs - so they have both performance and data integrity. > AND they also push their data off to other arrays. > > > > What Dan said. We run a smallish (only 3 terabytes) buncha storage here, > and have been using RAID forever. > > > > Contrary to what Len said RAID5 is NOT designed for data security, it is > designed for minimal downtime (If a drive fails, you can throw in a new one > and not take the raid offline while the RAID rebuilds itself.) > > > > Backups are your ONLY Data Security...we've experienced the very thing > Dan warns about: a RAID card goes bad and barfs all over the RAID 5. > Kablooey. We had to put in a new card and rebuild the RAID from tape, a > process that took about 32 hours at the time, and at that we lost a fair > chunk of data newer than three days old (RAID died mid-incremental backup) > > > > > Well so then my CCC scheduled backups should do what i need? I guess mainly > what I want to do is transfer files faster between drives and have every > thing on one machine except for a couple of esata externals for CCCs. > > John Carmonne > Yorba Linda USA > > > > > > > -- > You received this message because you are a member of G-Group, a group for > those using G3, G4, and G5 desktop Macs - with a particular focus on Power > Macs. > The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our > netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml > To post to this group, send email to [email protected] > For more options, visit this group at > http://groups.google.com/group/g3-5-list > -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list
