2 first partitions on every HDD

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geohei
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2 first partitions on every HDD

Postby geohei » Sun Aug 13, 2017 6:24 am

Hi.

Here a DSM 6.1.3 prepared 10TB HDD.
Can someone explain please what the initial 2.4GB and 2GB partitions are used for?
Every HDD has these, even if the total HDD capacity differs.

Code: Select all

root@europa:~# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.26.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): p
Disk /dev/sdb: 9.1 TiB, 10000831348736 bytes, 19532873728 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

Device       Start         End     Sectors  Size Type
/dev/sdb1     2048     4982527     4980480  2.4G Linux RAID
/dev/sdb2  4982528     9176831     4194304    2G Linux RAID
/dev/sdb3  9437184 19532668927 19523231744  9.1T Linux RAID
Last edited by geohei on Mon Aug 14, 2017 10:34 am, edited 1 time in total.
drabisan
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Re: 2 first partitions on every HDD

Postby drabisan » Sun Aug 13, 2017 9:19 am

DSM and swap. Each and every drive has it.
geohei
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Re: 2 first partitions on every HDD

Postby geohei » Sun Aug 13, 2017 9:43 am

Are both partitions synced continously?
drabisan
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Re: 2 first partitions on every HDD

Postby drabisan » Sun Aug 13, 2017 9:45 am

It's a RAID 1 config for both partitions. So yes.
geohei
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Re: 2 first partitions on every HDD

Postby geohei » Sun Aug 13, 2017 10:07 am

Sorry ... I believe a misunderstanding.

sda1 and sda2 exist also on Drive 2 (as sdb1 and sdb2) and Dirve 3 (as sdc1 and sdc2) and ...
Are all sdx1 (DSM) partitions mirrored between each other?
Are all sdx2 (swap) partitions mirrored between each other?

I believe the RAID functionalities start to take place only after sdx3 (included) upwards?
drabisan
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Re: 2 first partitions on every HDD

Postby drabisan » Sun Aug 13, 2017 5:14 pm

Yes. It's a RAID 1 no matter what RAID you configured.
Yes. Same as above.
Yes. Whatever RAID you choose applies to sdx3+.

It's easy to check it for yourself if you want to. Just plug one HDD from Synology into an pc/usb caddy and mount it in Linux.
geohei
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Re: 2 first partitions on every HDD

Postby geohei » Mon Aug 14, 2017 10:36 am

Ok, now I got it.
sdx1 and sdx2 are configured as RAID 1 accross all HDDs

Thanks for the clarification!

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