Nathan, Cliff - Thanks for the clarification! Think I understand this more now. Lustre can grow at the granularity of LUN size by adding it as another OST. Not in between. I presume the scenario is same for reduce/decreasing(take an OST offline and add to another MDT).
- Sridhar > -----Original Message----- > From: cliff white [mailto:[EMAIL PROTECTED] > Sent: Tuesday, January 09, 2007 11:21 AM > To: Nathaniel Rutman > Cc: Sridharan Ramaswamy (srramasw); lustre-discuss@clusterfs.com > Subject: Re: [Lustre-discuss] Logical volumes over Lustre storage > > Nathaniel Rutman wrote: > > Sridharan Ramaswamy (srramasw) wrote: > >> Is it possible to get traditional LVM like functionality > over Lustre > >> based storage? > >> > >> My understanding is Lustre can aggregate storage OSTs to provide a > >> single mount point. But the aggregate storage it provides can't be > >> carved out into different logical volumes, is this correct? > >> > >> For eg, assume each OST is 8GB > >> > >> node1: OST1, OST2, MDT > >> node2: OST3, OST4 > >> > >> Using *single* Lustre instance is it possible to provide two mount > >> points with 16GB each? And ability to administratively change the > >> storage available to each of those mount points, say > instead of 16GB > >> each to 20GB and 12GB. Something similar to lvextend, lvreduce. > > As Nathan mentions below you will be able to dynamically add > OSTS in the > future. However, you can _not split a single partition between two > filesystems (which is possible with LVM) so you would not be > able to split the 8GB LUN. You could start with 16GB, add an 8GB LUN > and grow to 24GB, (You can do this today, but you have to stop the > filesystem to change the config) but you could not add 1/2 > the LUN. So a > 12GB/20GB split with 8 GB LUNS is not possible, and will not > be possible > in the future. > cliffw > > >> > >> I presume you can achieve something like the above by creating two > >> Lustre instances(running in different ports) and mount > them separately > >> as 16GB filesystem. But that seems too much overhead. > >> > > They don't have to run in different ports, but yes, you can > achieve what > > you want by making two different Lustre filesystems. That > does mean you > > need two different MDTs. (Similarly, you would have to have two > > different filesystems on your LVM.) > > In Lustre 1.6 you can dynamically add OSTs to a filesystem > to increase > > the space available. > >> Appreciate any insights on this area. > >> > >> thanks, > >> Sridhar > >> > -------------------------------------------------------------- > ---------- > >> > >> _______________________________________________ > >> Lustre-discuss mailing list > >> Lustre-discuss@clusterfs.com > >> https://mail.clusterfs.com/mailman/listinfo/lustre-discuss > >> > > > > _______________________________________________ > > Lustre-discuss mailing list > > Lustre-discuss@clusterfs.com > > https://mail.clusterfs.com/mailman/listinfo/lustre-discuss > > > _______________________________________________ Lustre-discuss mailing list Lustre-discuss@clusterfs.com https://mail.clusterfs.com/mailman/listinfo/lustre-discuss
