-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Many many thanks for the detailled procedure.
I'll try in a few days with drbd9 and will let you know if something has to be changed (mainly because resources are created on the fly on each side). Julien Le 29/08/2018 à 14:32, David Bruzos a écrit : > Hi, I have lots of experience skipping the initial sync with ZFS zvols and > drbd 8.4.x. I have been using the "drbdadm -- --clear-bitmap > new-current-uuid <RESOURCE>" for years and never had a problem. This is > why it works: > > 1. New ZFS volumes are guaranteed to return only zero data for unwritten > blocks, so two new volumes are always in sync, if they have not been > written to. 2. Also, if you have a VM base image on two hosts, you can > clone the volumes in the image on each host and also skip the initial > sync, because both clones will be identical. Of course, I am asuming that > the base image was replicated via ZFS streams. 3. LVM volumes and most > other volume types will not work well, because they don't guarantee new > volumes to be zero-filled. However, depending on your use case, it is > often better to zero-fill your volumes manually (E.G. cat /dev/zero > >/dev/vg/vol0) and skip the sync. It does not seem reasonable, but given > the storage and network characteristics at play, it could be much much > better than doing an actual DRBD sync. 4. If in doubt, run a drbd verify > until you feel confidence in your process. > > * Typical way to skip the sync (at least this is my proven method): > > # drbdadm create-md <resource> - (do this on both nodes) # drbdadm up > <resource> - (do this on both nodes) # drbdadm -- --clear-bitmap > new-current-uuid <resource> - (do this on secondary node) # drbdadm > primary <resource> - (do this on primary node) # cat /proc/drbd - > (Enjoy!) > > In my opinion, having to replicate multi-tb volumes is an incredible waste > of time and resources, if it can be safely avoided. I've talked to many > people that patiently wait while their giant 4 TB VM volumes do their > initial sync and hog their environment's I/O in the process... > > I hope this helps you and others out there who are looking for a better > way... > > David > -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJbhrW0AAoJEOWv2Do/Mctu8TMP/3DYV8A+azXZLeq1AfRk/VE0 Db5rJkgjeNRvCIFdpr49m+bcFlrA/++Evlf/TdDnWH03Rq0rg8L44oEX9dN3aAqg 9QJpcPduXYaWpvBAOx3dD2RLpKhiHPUWFyMLBEXV9+X4fK8RbvXSMj/hTt9xQs1C Zf801bn5hlwl3m0o0kloWh2XdkAteG3t9E5WbUvb+6B+Qkn+/VkWtJ/gRKIQZv8H 3mvO/5kV3YcIaoP6vmVvKo37fH2A7Sj3AfpIUsOUCrLrqoW6vJbMXnW7SjfbkhVg vVlMNRRxDmfwGHqYQHUJDgOMJexVBZXxRUY7xcUJ4eSZ3HG/pG8r8Us9RBLp39SS DKDABmVhjbtHMQMXiLCBYyXj74hHfEON0SSW6UHWb+UVBbMyZrf93KJvRBD56dfv LspkZrb3mQ0q4TImG/MbTswMs0RraJUZqbmj9WALyPYTGTV/ORsE+g0KMV8gnTXM 4u4go9z5VQoDTah+aTcE3wpzdyDstd5i5p1CSMSeW/g9u1V5r2zKO6r39V4YRu14 Zoyv6J55y3+vmH25jqvIBJUkOaDsDCAlWWwE9pfyFPKQc/MmArGUWMuitKD0cgiP vTSaJ4hm+xFFiXgjLUNxvCyMVSgCmhLVnccsjiL1LTCvCav3QscfYZ6K6dBtIdxA NrmvY3d5zGDw7MW8VzvU =J/C6 -----END PGP SIGNATURE----- _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
