-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 9/11/12 9:01 AM, Edward Ned Harvey (lopser) wrote: > I'm being exposed to drbd for the first time, and I'm not > impressed. I'm finding it's a sort-of inflexible kludge for the > purpose of mirroring storage locally and remotely. > > What about md or lvm mirroring to an iscsi device? Experience? > Opinions? > > Ideally, I'd love to see something comparable to zfs mirroring with > an iscsi device. That is - If the iscsi device disappears and > reappears, it only needs to resilver the blocks that changed in the > meantime. And the iscsi device is never inconsistent. (Both > characteristics lacking by drbd). > > But I don't have a lot of experience with md or lvm mirroring.
Just a single data point: Recently I had the opportunity to resilver a raid1 mirror that uses md. In its defence, I will say that there had been no attempt to optimise, configure or in any way improve the experience (is there anything that can be done to improve this?). It had just been created with: mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1 However, although resilvering the mirror while the device is active is possible, the performance was inadequate to the point of uselessness. After several hours it was killed at <40% complete. (Hardware was some modern quad core server with 96G and 15K rpm disks, otherwise more or less completely inactive at the time). It was easier to copy the data (few 100s of GB) off the (1TB?) filesystem and rebuild the mirror from scratch. Perhaps my surprise was only due to my ignorance of the underlying mechanisms. - -- Duncan Hutty http://www.allgoodbits.org -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iEYEARECAAYFAlBPPusACgkQCFuTFybf1wrJjQCfZ2tk5wR2wWFPjtaNKr6MXkqz mK4AnAhgkMd92ltdn9G8ptL7/4L+mgHo =ZIkE -----END PGP SIGNATURE----- _______________________________________________ Tech mailing list Tech@lists.lopsa.org https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
