Frank Steiner wrote: > With the profile ignoring the FUA bit, copying or deleting directories > of e.g. 10M with a about 1000 files is factor 5 faster than with the > profile honoring the FUA bit. > FUA bit is normally combined with write-thru scsi command that bypasses storage write cache. I would imagine it needs to well synchronize various pieces before issuing this command. It could hurt the performance if not done well, particularly for meta data. So your result is not surprising. > We export with the "sync" option. Does that option maybe set the FUA bit > for all write operations on the NFS server? > It depends on how the filesystem (and its associated disk subsystem) is implemented. The "sync" export option itself has a heavy performance impact, regardless how FUA bit is handled. Some vendors uses specialized HW (e.g. NVRAM) to alleviate this performance hit. If your filesystem doesn't have this type of support, you should expect "sync" option runs much much slower than "async". It is a choice (or balance) between cost, performance, and data reliability. Don't you have the vendor's support group to go ? Better get this answer from the storage vendor directly. -- Wendy ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ NFS maillist - NFS@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/nfs _______________________________________________ Please note that nfs@xxxxxxxxxxxxxxxxxxxxx is being discontinued. Please subscribe to linux-nfs@xxxxxxxxxxxxxxx instead. http://vger.kernel.org/vger-lists.html#linux-nfs -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
