ASM overhead?

From: jared <jared_at_hwai.com>
Date: Tue, 10 Jul 2007 13:42:49 -0700
Message-ID: <1184100169.277865.214590@q75g2000hsh.googlegroups.com>

Consider the following excerpt from iostat:

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
-------            ---   ----------   ----------   --------   --------
sdb               9.38         0.00      4340.12          0      21744
sdb1              6.19         0.00      2887.03          0      14464

sdc               8.78         0.00      4298.60          0      21536
sdc1              5.79         0.00      2864.67          0      14352

sdd               9.58         0.00      4311.38          0      21600
sdd1              6.19         0.00      2871.06          0      14384

sde              14.17        12.77      5863.47         64      29376
sde1              9.38         9.58      3883.43         48      19456

These devices make up part of an an LVM managed by the Oracle facility ASM (Automated Storage Management). There is nothing else there. Why, then, would there be such a discrepancy between the overall volume (e.g., sdc) and the actual device Oracle uses (e.g., sdc1)? FYI, these are LUNs on an EMC DMX, latest software, patched up, etc. Server is a Proliant 580, 4 dual-core Xeons, 16GB memory, RHAS4 patched up.

Does anyone have any experience with this phenomenon? Received on Tue Jul 10 2007 - 15:42:49 CDT