Re: [CentOS] [CentOS-docs] Updating the RAID1 HowTo to CentOS 6
On 05/02/12 18:47, Gianni Giardina wrote: Hi. The following HowTo on the CentOS Wiki: http://wiki.centos.org/HowTos/Install_On_Partitionable_RAID1 valid for CentOS 5, has not been updated to CentOS 6, yet. I found it very useful during the glorious CentOS 5 days and now that I've successfully ported my RAID1 experience to CentOS 6, I'd like to share it with the Community. I have a question regarding partionable RAID : why should the --metadata=0.90 be used? in my man page (centos 6.2) i have this : -e, --metadata= Declare the style of RAID metadata (superblock) to be used. The default is 1.2 for --create, and to guess for other operations. The default can be overridden by setting the metadata value for the CREATE keyword in mdadm.conf. Options are: 0, 0.90 Use the original 0.90 format superblock. This format limits arrays to 28 component devices and limits component devices of levels 1 and greater to 2 terabytes. It is also possible for there to be confusion about whether the superblock applies to a whole device or just the last partition, if that partition starts on a 64K boundary. 1, 1.0, 1.1, 1.2 default Use the new version-1 format superblock. This has fewer restrictions. It can easily be moved between hosts with different endian-ness, and a recovery operation can be checkpointed and restarted. The different sub-versions store the superblock at different locations on the device, either at the end (for 1.0), at the start (for 1.1) or 4K from the start (for 1.2). 1 is equivalent to 1.2. default is equivalent to 1.2. given the existence of 2+ tb hdd, metadata 0.9 is no go from the start ... so, why 0.9 ? Thanks, Adrian ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [CentOS-docs] Updating the RAID1 HowTo to CentOS 6
On Mon, May 7, 2012 at 1:24 PM, Adrian Sevcenco adrian.sevce...@cern.ch wrote: On 05/02/12 18:47, Gianni Giardina wrote: Hi. The following HowTo on the CentOS Wiki: http://wiki.centos.org/HowTos/Install_On_Partitionable_RAID1 valid for CentOS 5, has not been updated to CentOS 6, yet. I found it very useful during the glorious CentOS 5 days and now that I've successfully ported my RAID1 experience to CentOS 6, I'd like to share it with the Community. I have a question regarding partionable RAID : why should the --metadata=0.90 be used? in my man page (centos 6.2) i have this : -e, --metadata= Declare the style of RAID metadata (superblock) to be used. The default is 1.2 for --create, and to guess for other operations. The default can be overridden by setting the metadata value for the CREATE keyword in mdadm.conf. Options are: 0, 0.90 Use the original 0.90 format superblock. This format limits arrays to 28 component devices and limits component devices of levels 1 and greater to 2 terabytes. It is also possible for there to be confusion about whether the superblock applies to a whole device or just the last partition, if that partition starts on a 64K boundary. 1, 1.0, 1.1, 1.2 default Use the new version-1 format superblock. This has fewer restrictions. It can easily be moved between hosts with different endian-ness, and a recovery operation can be checkpointed and restarted. The different sub-versions store the superblock at different locations on the device, either at the end (for 1.0), at the start (for 1.1) or 4K from the start (for 1.2). 1 is equivalent to 1.2. default is equivalent to 1.2. given the existence of 2+ tb hdd, metadata 0.9 is no go from the start ... so, why 0.9 ? I always thought it was a huge advantage for software raid that the kernel would autodetect and assemble the components. Is there a way to make that happen with 1.x metadata? -- Les Mikesell lesmikes...@gmail.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [CentOS-docs] Updating the RAID1 HowTo to CentOS 6
On 05/07/2012 08:24 PM, Adrian Sevcenco wrote: On 05/02/12 18:47, Gianni Giardina wrote: Hi. The following HowTo on the CentOS Wiki: http://wiki.centos.org/HowTos/Install_On_Partitionable_RAID1 snip given the existence of 2+ tb hdd, metadata 0.9 is no go from the start ... so, why 0.9 ? 0.90 is needed so older GRUB can boot from that RAID1 partition. -- Ljubomir Ljubojevic (Love is in the Air) PL Computers Serbia, Europe Google is the Mother, Google is the Father, and traceroute is your trusty Spiderman... StarOS, Mikrotik and CentOS/RHEL/Linux consultant ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
