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On 10/18/2010 4:28 AM, Habony, Zsolt wrote: > > I worry about head thrashing. Why? If your SAN group gives you a LUN that is at the opposite end of the array, I would think that was because they had already assigned the space in the middle to other customers (other groups like yours, or other hosts of yours.) If so, don't you think that all those other hosts and customers will be reading and writing from that array all the time anyway? I mean if the heads are going to 'thrash', then they'll be doing so even before you request your second LUN right? Adding your second LUN to the mix isn't going to seriously change the workload on the disks in the array. > Though memory cache of large storage should make the problem > easier, I would be more happy if I can be sure that zpool will not > be handled as a stripe. > > Is there a way to avoid it, or can we be sure that the problem does > not exist at all ? > As I think the logic above suggests, If the problem exists, it exists even when you only have 1 LUN. -Kyle -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (MingW32) iQEcBAEBAgAGBQJMvFeKAAoJEEADRM+bKN5wuc4IALPTIrGcAq6TWa95yrA/DCWp vu2K7+pwSvz/IRIP+C6Y+qvWm/Km+UdtRu6PKb8G/DF8xp5vEnkqXdRSNDC6FlpR EwSNavS7ij87bN6fuBiw6E02GZtADi2RptPKgyGz1FT3wPDHS8SQKtA59DwrWJNS ckHUi+9BwngL4p7E0C+8pcahyF7QmtTm3DpL3y4AZ+7O+c/wPcIwLZ3dI6yQU8vd KuRe6h/xCHffKH9gHoXJf0pG4e5iA8XP+lt7DlJGPxRYzZil0Rr5JA67uGqEf/VY FbhAtXqWrHkNSd2sk1bIJVj7OFCS6j/NXMkV/Dt6OUH2Gkucl1nBs4yIAQ9Hu3s= =I+w1 -----END PGP SIGNATURE----- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
