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ntate

1 Rookie

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11 Posts

1913

June 15th, 2021 07:00

Virtual Disk UUID representation

Hi Dell

Using perccli to create a RAID1 VD.

This has no representation in /dev/disk/by-uuid.

Only after if a LVM wat created. Like sda1, sda2.

 

Q: Are there a possibility that this VD can have a UUID represented in /dev/disk/by-uuid?

This is SUSE related but can be any Linux flavor I suppose.

To see /dev/disk/by-uuid/sda would be great. Before a LVM is present.

Thanks so much.

Jan

DELL-Chris H

Moderator

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9.5K Posts

June 17th, 2021 07:00

I am not certain, but It sounds like you want to see a link named "sda" in the by-* directories? But if that was the case, you would just use /dev/sda. In the output you posted we see links that resolve to "sda" three times, exactly as it should be.
./by-id:
scsi-362cea7f06a7f5800284a0335358f2cb5 -> ../../sda
wwn-0x62cea7f06a7f5800284a0335358f2cb5 -> ../../sda
./by-path:
pci-0000:01:00.0-scsi-0:2:0:0 -> ../../sda
So if your goal is an automated installation where you don't already know the SAS WWNs, "/dev/disk/by-path/pci-0000:01:00.0-scsi-0:2:0:0" will work. If your target systems aren't 100% standardized in their configuration you may need to add some logic in the installation script to use wildcards. For example, "/dev/disk/by-path/pci-0000:0?:00.0-scsi-*" would return all VDs presented by SCSI (/SAS) controllers detected on PCI busses 0x00 through 0x0F.
I should point out though that on a regular PowerEdge server the PCI bus number assigned to the PERC (by the BIOS) is not guaranteed to be 0x1, nor even to be the same value every time it powers up. I've seen 0x1, 0x2, and 0x3. Some systems we offer take extra (hidden, not user-configurable) steps to forcibly pin that down to a single value but it is not common.
Let me know if this helps.

DELL-Chris H

Moderator

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9.5K Posts

June 15th, 2021 12:00

Ntate,

 

I was starting to suggest (rescan-scsi-bus.sh), but there is more at work here. There's a good write-up at https://dell.to/3gzsvSs ,
but the short version is that /dev/disk/by-uuid is only for filesystems . For the parent device you can see entries in /dev/disk/by-id or /dev/disk/by-path. If you care about the UUID of the partition instead of the filesystem, use /dev/disk/by-partuuid.

 

 

Let me know if this helps.

 

 

 

 

ntate

1 Rookie

 • 

11 Posts

June 17th, 2021 05:00

Hello Chris

Thank you for this information and reference.

Having the Virtual Disk represented in by-id or in by-path would be sufficient

as /dev/disk/by-id/sda or /dev/disk/by-path/sda.
Then you could select it (in install script) - as it is the parent.

Used in Kiwi.

Now it is represented as below, this changes per system etc.
/dev/disk # l -Ro
drwxr-xr-x 7 root 140 Jun 2 11:04 ./
drwxr-xr-x 19 root 4660 Jun 2 11:05 ../
drwxr-xr-x 2 root 320 Jun 2 11:05 by-id/
drwxr-xr-x 2 root 60 Jun 2 11:05 by-label/
drwxr-xr-x 2 root 60 Jun 2 11:04 by-partuuid/
drwxr-xr-x 2 root 160 Jun 2 11:05 by-path/
drwxr-xr-x 2 root 60 Jun 2 11:05 by-uuid/

./by-id:
total 0
drwxr-xr-x 2 root 320 Jun 2 11:05 ./
drwxr-xr-x 7 root 140 Jun 2 11:04 ../
lrwxrwxrwx 1 root 10 Jun 2 11:04 dm-name-ram0p1 -> ../../dm-0
lrwxrwxrwx 1 root 10 Jun 2 11:04 dm-uuid-part1-devnode_1:0_Wh5pYvM -> ../../dm-0
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-Dell_Express_Flash_NVMe_P4610_3.2TB_SFF_PHLN013001M93P2BGN -> ../../nvme2n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-Dell_Express_Flash_NVMe_P4610_3.2TB_SFF_PHLN013001MH3P2BGN -> ../../nvme3n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-Dell_Express_Flash_NVMe_P4610_3.2TB_SFF_PHLN013001Q83P2BGN -> ../../nvme1n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-Dell_Express_Flash_NVMe_P4610_3.2TB_SFF_PHLN013001Z23P2BGN -> ../../nvme0n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-Dell_Express_Flash_NVMe_P4610_3.2TB_SFF_PHLN013002AZ3P2BGN -> ../../nvme4n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-eui.01000000010000005cd2e4052b395251 -> ../../nvme0n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-eui.01000000010000005cd2e40905395251 -> ../../nvme4n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-eui.01000000010000005cd2e4963e395251 -> ../../nvme2n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-eui.01000000010000005cd2e49e3e395251 -> ../../nvme3n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 nvme-eui.01000000010000005cd2e4e73e395251 -> ../../nvme1n1
lrwxrwxrwx 1 root 9 Jun 2 11:04 scsi-362cea7f06a7f5800284a0335358f2cb5 -> ../../sda
lrwxrwxrwx 1 root 9 Jun 2 11:04 wwn-0x62cea7f06a7f5800284a0335358f2cb5 -> ../../sda

./by-label:
total 0
drwxr-xr-x 2 root 60 Jun 2 11:05 ./
drwxr-xr-x 7 root 140 Jun 2 11:04 ../
lrwxrwxrwx 1 root 10 Jun 2 11:04 ROOT -> ../../dm-0

./by-partuuid:
total 0
drwxr-xr-x 2 root 60 Jun 2 11:04 ./
drwxr-xr-x 7 root 140 Jun 2 11:04 ../
lrwxrwxrwx 1 root 10 Jun 2 11:04 bcc0a515-01 -> ../../dm-0

./by-path:
total 0
drwxr-xr-x 2 root 160 Jun 2 11:05 ./
drwxr-xr-x 7 root 140 Jun 2 11:04 ../
lrwxrwxrwx 1 root 9 Jun 2 11:04 pci-0000:01:00.0-scsi-0:2:0:0 -> ../../sda
lrwxrwxrwx 1 root 13 Jun 2 11:04 pci-0000:42:00.0-nvme-1 -> ../../nvme0n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 pci-0000:43:00.0-nvme-1 -> ../../nvme1n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 pci-0000:44:00.0-nvme-1 -> ../../nvme2n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 pci-0000:45:00.0-nvme-1 -> ../../nvme3n1
lrwxrwxrwx 1 root 13 Jun 2 11:04 pci-0000:c7:00.0-nvme-1 -> ../../nvme4n1

./by-uuid:
total 0
drwxr-xr-x 2 root 60 Jun 2 11:05 ./
drwxr-xr-x 7 root 140 Jun 2 11:04 ../
lrwxrwxrwx 1 root 10 Jun 2 11:04 73932d61-a146-4211-8b8c-e48491ebe8a7 -> ../../dm-0

Not Possible?

Regards,
Jan

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