[lustre-discuss] Questions about migrate OSTs from ldiskfs to zfs

Fernando Perez fperez at icm.csic.es
Tue Feb 23 05:23:41 PST 2016

Hi all.

We have a 230 TB small lustre system. We are using lustre 2.4.1 with zfs 
0.6.2 installed in the OSSs. The lustre architecture is the following:

1 MDS +1  MDT in the same server + 3 OSS with 15 ldiskfs OSTs (external 
disks some with fibre controllers and SAS disks and others Coraid aoe 
cabinet with standard SATA disks).

We need to replace 9 OSTs by 2 zfs OSTs due to hardware problems: 
replace Coraid storage by a Supermicro SAS JBOD with twenty disks, each 
disk has 8 TB.

I have some questions that I hope you can help me to answer:

- What can I do with the inactive osts numbers? Acording to lustre 
manual I suppose that I can't erase them,
- I don't need to restore OST configuration files to replace ldiskfs 
OSTs by zfs OSTs, do I?
- Dou you recommend to do a lustre update before replace the OSTs by the 
new zfs OSTs?
- I have read in the list that there are problem with the last 
zfsonlinux release and lustre only works with zfsonlinux 0.6.3. Is this 

Thanks in advance for your help.


Fernando Pérez
Institut de Ciències del Mar (CMIMA-CSIC)
Departament Oceanografía Física i Tecnològica
Passeig Marítim de la Barceloneta,37-49
08003 Barcelona
Phone:  (+34) 93 230 96 35

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