On 09/07/21 13:27, David T-G wrote: > Hi, all -- > > I have a 1T drive > > jpo:~ # parted /dev/sdb print > Model: ATA ST31000524AS (scsi) > Disk /dev/sdb: 1000GB > Sector size (logical/physical): 512B/512B > Partition Table: msdos > Disk Flags: > > Number Start End Size Type File system Flags > 1 1049kB 1000GB 1000GB primary ntfs type=07 > > jpo:~ # smartctl -i /dev/sdb > smartctl 7.0 2019-05-21 r4917 [x86_64-linux-5.3.18-lp152.78-default] (SUSE RPM) > Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org > > === START OF INFORMATION SECTION === > Model Family: Seagate Barracuda 7200.12 Barracuda ... DO NOT USE THIS IN A PARITY RAID ARRAY !!! Mirroring as you plan here is okay. > Device Model: ST31000524AS > Serial Number: 9VPG4SHD > LU WWN Device Id: 5 000c50 04d20d244 > Firmware Version: JC45 > User Capacity: 1,000,204,886,016 bytes [1.00 TB] > Sector Size: 512 bytes logical/physical > Rotation Rate: 7200 rpm > Device is: In smartctl database [for details use: -P show] > ATA Version is: ATA8-ACS T13/1699-D revision 4 > SATA Version is: SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s) > Local Time is: Thu Jul 8 11:32:27 2021 UTC > SMART support is: Available - device has SMART capability. > SMART support is: Enabled > > and also two 500G drives > > jpo:~ # parted /dev/sdc print > Model: ATA WDC WD5000AAVS-0 (scsi) > Disk /dev/sdc: 500GB > Sector size (logical/physical): 512B/512B > Partition Table: gpt > Disk Flags: > > Number Start End Size File system Name Flags > 1 1049kB 356GB 356GB ata-WDC_WD5000AAVS-00ZTB0_WD-WMASU06 raid > 2 356GB 495GB 139GB raid > 4 495GB 500GB 5001MB reiserfs wwn-0x50014ee055b724ad > > jpo:~ # smartctl -i /dev/sdc > smartctl 7.0 2019-05-21 r4917 [x86_64-linux-5.3.18-lp152.78-default] (SUSE RPM) > Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org > > === START OF INFORMATION SECTION === > Model Family: Western Digital Caviar Green > Device Model: WDC WD5000AAVS-00ZTB0 > Serial Number: WD-WMASU0686160 > LU WWN Device Id: 5 0014ee 055b724ad > Firmware Version: 01.01B01 > User Capacity: 500,107,862,016 bytes [500 GB] > Sector Size: 512 bytes logical/physical > Device is: In smartctl database [for details use: -P show] > ATA Version is: ATA8-ACS (minor revision not indicated) > SATA Version is: SATA 2.5, 3.0 Gb/s > Local Time is: Thu Jul 8 11:32:35 2021 UTC > SMART support is: Available - device has SMART capability. > SMART support is: Enabled > > that I plan to stripe together to use to protect the first. The Caviars > are listed as variable speed, but in practice they apparently are just > 5400 rpm, so I'd like to take advantage of striping to make them as fast > as possible. Caviar Green ??? Caviars should be okay, but the "green" moniker makes me nervous. Check SCT/ERC, but striping/mirroring will be fine. > This isn't the black magic ;-) of RAID10-on-two-drives, > so I don't have to think of one as "front" and one as "back", but do I > want more than one partition on each to stripe 4 or 6 slices to avoid > hammering on one, or do I just go with each device as a whole and let > mdadm handle the magic for me? > > I also plan to use a partition on the 1T drive, but once I have the > striped metadevice do I particularly want or particlularly not want to > slice a partition out of it? I figured I would partition since that > would let me exactly match the mirror halves to each other. > > Oh, and to make this more fun the two 500s are actually part of a 3-dev > RAID5 set holding the data to migrate to the 1T to then mirror, so I > don't get to destructively play with this a dozen times :-) > Okay, the simple approach. Create a single-device mirror using the 1TB and the special device "missing". Copy everything across and make sure it's all okay. (I'm assuming you can safely wipe this drive as it has nothing on it you wish to keep.) Create a striped device using the two 500GB drives. Add the striped device to the 1TB mirror. Plan to replace all the disks with something like Seagate Ironwolves or Toshiba N300s in the near future :-) https://raid.wiki.kernel.org/index.php/Linux_Raid Read especially the page on timeout mismatch as this DOES apply to your Barracuda !!! Cheers, Wol
