Re: Calling all raid experts
I'd take a look at vinum, the software RAID array. Performance seems as good as hardware-based RAID solutions. Under 5.1-RELEASE I've been told that the boot partition can be on a vinum volume; in 4.8 that's not possible but I've used extra space to create several duplicate boot partitions. I've always used SCSI, but the low cost of ATA devices would certainly make me look at them today. I've also been told that you'll need as many ATA busses as drives, since slave devices slow down ATA speed. Mike Squires ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: Calling all raid experts
> Greetings, > I need to build a file server for our marketing departments documents > and images. I want to use Freebsd. Since the data is large, and > backups would be difficult I was wondering if RAID would be a solution. > > I thought that RAID 5 would be the ticket, but after reading up on it, > maybe not. > > Isn't RAID 5 the one where if a disk fails, you plug a new one it and it > regenerates the lost data ? > It does that through the use of some checksum data that's spread across the disks. Reads on raid 5 can be significantly faster than single disk because data is striped across multiple disks, but writes don't get as much of a boost because for every write, there are several operations, including the recalculation of a checksum, and the writing of both the checksum and data, then a re-reading of them. Writes are usually faster than single disk writes, but the gain is not nearly as much as with reads. Ken ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: Calling all raid experts
While RAID5 gives efficient use of disk space for situations where you have 5 drives, its NOT a substitute for backups nor is it necessarily the best thing to use depending on the application. Writes for example are VERY slow and depending on the card, direct reads can not be that great either. Having a mirror of your file system containing /home/data/very-important-big-file will not stop rm /home/data/very-important-big-file It just obliterates it off all your drives. If you do a lot of reading and writing of the disk, RAID5 is not necessarily the best. With IDE drives dirt cheap, consider something like RAID1+0 (aka RAID10). It offers the best of speed and safety, at the expense of space. In some cases, RAID1 might do you well. With the 3ware cards, reads are optimized and writes are hardly penalized. If you need a lot of space, consider the 3ware cards. Solid FreeBSD support, are relatively inexpensive, and have done me VERY well over the years. ---Mike At 10:26 AM 29/07/2003 -0500, Darryl Hoar wrote: Greetings, I need to build a file server for our marketing departments documents and images. I want to use Freebsd. Since the data is large, and backups would be difficult I was wondering if RAID would be a solution. I thought that RAID 5 would be the ticket, but after reading up on it, maybe not. Isn't RAID 5 the one where if a disk fails, you plug a new one it and it regenerates the lost data ? thanks, Darryl ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]" ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: Calling all raid experts
On Tue, Jul 29, 2003 at 10:26:19AM -0500 or thereabouts, Darryl Hoar wrote: > Greetings, > I need to build a file server for our marketing departments documents > and images. I want to use Freebsd. Since the data is large, and > backups would be difficult I was wondering if RAID would be a solution. > > I thought that RAID 5 would be the ticket, but after reading up on it, > maybe not. > > Isn't RAID 5 the one where if a disk fails, you plug a new one it and it > regenerates the lost data ? You have two main choices: RAID-1 and RAID-5. If N is the number of disks and M is the size of the smallest disk, then... RAID-1 will give you M amount of space. As long as one disk still works, you can have multiple disks fail at the same time; just replace them and your data's back. Reads execute at N times the speed of single-drive reads. Writes are normal speed. RAID-5 will give you M*(N-1) amount of space. If one disk fails, you can replace it with no loss of data. But if two disks fail at the same time, your data's toast. Reads execute at about N times the speed of single-drive reads. Writes are slower than normal speed. -- Josh > > thanks, > Darryl > ___ > [EMAIL PROTECTED] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "[EMAIL PROTECTED]" ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Calling all raid experts
Greetings, I need to build a file server for our marketing departments documents and images. I want to use Freebsd. Since the data is large, and backups would be difficult I was wondering if RAID would be a solution. I thought that RAID 5 would be the ticket, but after reading up on it, maybe not. Isn't RAID 5 the one where if a disk fails, you plug a new one it and it regenerates the lost data ? thanks, Darryl ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
