-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 12/19/2012 11:45 AM, Jim Meyering wrote: > Phillip Susi wrote: >> Sure, take a 4 disk raid5 with 256k stripe factor. > > Am I misunderstanding something? 256k is both smaller than 1MiB and > *is* a power of 2. I was asking if you'd seen values *not* like > that.
A 4 disk raid 5 with 256k stripe factor uses 256k from each of 3 disks ( 4th is parity ), giving a stripe width and thus an optimal alignment of 768k. > I guess it comes down to whether there are systems that return > bogus values there, and whether there are systems that return legit > values smaller < 1MiB, like I was asking about above. I'm not aware of any known bugs where the kernel returns inappropriate values, but there are plenty of raid configurations that do use < 1MiB and/or non power of two alignments. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iQEcBAEBAgAGBQJQ0gP5AAoJEJrBOlT6nu75wGsIANy5bKhItbmLk8GDq75vpAmA YO2IU35Rn73XoLFej4YCXzsduIS0eF7/Q2z/q70UwnBL/A1e9Zz9HpC1VbNEkQig NBDjg0UHtzGWIKmQl69qW7USOrDxaqRek7/h/eA4EFR7evKMw6hPwmc5ef2Olmqy DqVq73vsAIC+J4029JUVGy72Fv9GaiW6Ijw2/GNmL6sjjh/WZzl/09G3a7a8YQru zYPo2ZeX1gSiXSn7ZsOAFAT2xPHGLofEp8vaFPfqw3dZCfliNrQOlPAR8YMj2ll9 YSFPj9kygHf4gfLVpBl/uBso07y/mpIrPRxr18gWRbYjnlLLgo7vdZLm1zbHXnI= =9NB8 -----END PGP SIGNATURE-----
