xfs_growfs / planned resize / performance impact

[Eric Sandeen]

On 7/31/12 8:56 AM, Stefan Priebe - Profihost AG wrote:
> Hello list,
> 
> i'm planning to create a couple of VMs with just 30GB of space while using xfs as the main filesystem.
> 
> Now i alreay know that some of the VMs will grow up to 250GB while resizing the block device and using xfs_growfs.
> 
> Should i take care of that and format these disks with special parameters?
> 
> I've discovered that a 500GB volume has agcount=4 and 64000 blocks of internal log - while a 300GB volume resized to 500GB has agcount 7 ad only 40960 blocks of internal log.
> 
> Is it a problem if this grow will happen in small portions (30GB => 50GB => 75GB => 100GB => ... 300GB)?

This incremental part doesn't matter a bit.  The first mkfs will choose the AG count & size according to defaults; further growth after this will add new (possibly partial) AGs of that pre-chosen size.

-Eric

> Thanks!
> 
> Greets,
> Stefan
> 
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