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martineg
Asked: 2012-07-24 06:59:38 +0800 CST

Online resize of large ext3 file system - is performance affected?

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I am planning for a resize of a rather large file system hosting an Oracle instance (one of several on the same server). The disk is 4 TB striped over several LUNs, I'm increasing by 1 TB keeping the same stripe width. As we usually use Oracle ASM for databases, I'm not sure how big of an impact the online resize will have on both the database being extended and also the rest of the system.

Are there any rules of thumb on duration and performance impact of a resize2fs on file system of this size?

rhel5

1 Answers

  1. As an authoritative answer from the main fsck.ext2/3 developer:

    To a first order approximation, it's roughly 1.7 the times of an fsck. Resize2fs requires that you do a freshly checked filesystem, and then resize2fs itself needs to scan through the filesystem to relocate any blocks needed to expand the group descriptor table. It could take less time, but if you want to be absolutely staff, budget for 2 times a full fsck time.

    http://sourceforge.net/projects/e2fsprogs/forums/forum/7053/topic/2009143

    So given the characteristics of the load, performance impact would be similar to what fsck -n does to your system - you should be able to benchmark that at a time of day when storage is rather quiet without much impact.

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