Hi,

I got error "invalid expansion" when trying to add another HDD to my current raidz2. Can anyone help me fix it?

I checked Unraid log and there is error "null): does not support RAIDZ expansion"

Nov 22 13:07:18 Tower kernel: mdcmd (30): import 28
Nov 22 13:07:18 Tower emhttpd: import 30 pool device: (sdc) WDC_WUH721818ALE6L4_3GJ6XYWE
Nov 22 13:07:18 Tower emhttpd: import 31 pool device: (sdg) WUH721818ALE6L4_3GG2ZZ0E
Nov 22 13:07:18 Tower emhttpd: import 32 pool device: (sde) WUH721818ALE6L4_3GG2N49E
Nov 22 13:07:18 Tower emhttpd: import 33 pool device: (sdd) WDC_WUH721818ALE6L4_3GJ853NE
Nov 22 13:07:18 Tower emhttpd: import 34 pool device: (sdf) WUH721818ALE6L4_3GG1RB7E
Nov 22 13:07:18 Tower emhttpd: import 35 pool device: (sdb) WDC_WUH721818ALE6L4_3GH3WNLE
Nov 22 13:07:18 Tower emhttpd: (null): does not support RAIDZ expansion
Nov 22 13:07:18 Tower emhttpd: slowpoke: invalid expansion: not multiple of 5
Nov 22 13:07:18 Tower emhttpd: /sbin/blkid /dev/sda1 2>&1
Nov 22 13:07:18 Tower emhttpd: /dev/sda1: LABEL_FATBOOT="UNRAID" LABEL="UNRAID" UUID="190F-231C" BLOCK_SIZE="512" TYPE="vfat" PARTUUID="b7c79597-01"

Unraid 7.2.2

CPU Intel 12100

RAM 64GB

Edited November 22, 2025Nov 22 by TinTin
add spec

Did you upgrade the pool?

What do you mean by upgrade the pool? Just updated Unraid from 7.1.4 to 7.2.2 today, i though it's enough.

Can you share the document?

It's in the release notes:

Yes, that's it. It's working now 😄

Someone should add this to the official ZFS document.