Le Thu, 27 Dec 2007 16:23:14 +0800, "Wang Yu" <wangyuict@xxxxxxxxx> a écrit : > 1.Why the performances under different subdirs varies so much? for > example in /mnt/test/0 the performance is 72/80, while in /mnt/test/1 > the performance is 49/53 I didn't had a precise look at your numbers, but there's one factor that can explain this performance variation: the read/write performance of an hard disk is not homogenous. The beginning of the disk is stored on the further cylinders from the center, while the end of the disk is stored on the cylinders close to the center. Because the disk rotation speed is constant, and the information density is constant, the raw performance of the disk is not the same for all cylinders. The performance degradation can be up to 50% when comparing performances at the beginning of the disk and at the end of the disk. Sincerly, Thomas -- Thomas Petazzoni, thomas.petazzoni@xxxxxxxx, http://thomas.enix.org Jabber, thomas.petazzoni@xxxxxxxxx Toulibre, http://www.toulibre.org - APRIL, http://www.april.org Fingerprint : 0BE1 4CF3 CEA4 AC9D CC6E 1624 F653 CB30 98D3 F7A7
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