Copying parition tables (only) on two GPT HDDs of 4TB each

Question

I have two hdds of 4TB each on CentOS 7. I need to copy partitions of one to the other so that I can use the second to take periodic backups from the first. Tried sgdisk using -R option but it did not help, while parted was able to read correctly the information. The output is as follows:

# parted -ml | sed 's/^/    /'
BYT;
/dev/sda:4001GB:scsi:512:4096:gpt:ATA WDC WD40EFRX-68W:;
1:1049kB:53.5MB:52.4MB:fat16:EFI System Partition:boot;
2:53.5MB:263MB:210MB:xfs::;
3:263MB:537GB:537GB:xfs::;
4:537GB:554GB:17.2GB:linux-swap(v1)::;
5:554GB:4001GB:3446GB:xfs::;

BYT;
/dev/sdb:4001GB:scsi:512:4096:gpt:ATA WDC WD40EFRX-68W:;
1:1049kB:53.5MB:52.4MB:fat16:EFI System Partition:boot;
2:53.5MB:263MB:210MB:xfs::;
3:263MB:525GB:524GB:xfs::;
4:525GB:541GB:16.8GB:::;
5:541GB:4001GB:3459GB:::;
#

Keeping in view of having to mount them together, how could the partitions be cloned?

Edit: I was able to accomplish by using the following as mentioned elsewhere:

sgdisk --backup=table /dev/sda
sgdisk --load-backup=table /dev/sdb
sgdisk -G /dev/sdb

But I am not sure if it is still safe to reboot. Help please!

Why are you doing backups this way and not with a purpose built tool? — MDMarra, Jul 03 '16 at 11:48
Agreed with @MDMarra; I'd like to know more about what you're trying to do. It sounds a bit like you need LVM snapshots and a backuptool. — Halfgaar, Jul 04 '16 at 18:44

score 1 · Accepted Answer · answered Jul 04 '16 at 18:41

1

Just want to add that the -R option of sgdisk does exactly what you are doing in the first two steps.

sgdisk -R /dev/sdb /dev/sda
sgdisk -G /dev/sdb

What do you do next? Mount the partitions and rsync them over each other?

answered Jul 04 '16 at 18:41

chutz

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Thanks. I want to `rsync` periodically corresponding partitions. After mirroring, the HDD will be umounted. – Quiescent Jul 05 '16 at 16:11

Copying parition tables (only) on two GPT HDDs of 4TB each

1 Answers1