Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
/ 2005-04-22 14:12:58 +0200 \ Seuberth, Frank: > Hello, > > i am new to 0.7.x Version of drbd and have some questions. > At first my configuration in the testing i am doing now: > SLES9 and drbd 0.7.x (what ever i will have after online update). > > 2 Systems, each configured : > 3 Physical disks (hda/hdb/hdc 36GB each) > hda1, swap, 1.5GB, software raid1 local to hdb1 > hda2, / ext3, 15GB, software raid1 local to hdb2 a note about (software) raid1 with IDE: don't mirror the master to the slave on the same IDE channel. always mirror between different channels, e.g. hda <-> hdc. > hda4 ?? mtadata, upto 1GB raid 1 local to hdb4 ??? > hda3, /vol01 ext3, 18GB, drbddevice to node B /hda3 > hdb3, /vol02 ext3, 18GB, drbddevice to node B /hdb3 > hdc1, /vol03 ext3, 36GB, drbddevice to node B /hdc1 > > Here are my questions : > I like to put the metadata on a physical partition. > Is this partition yust a "raw device" with the parition > type linux native or must there be a filesystem on it ? no file system. the partition/block device is used as is. (raw, if you want, though "raw devices" as a keyword is a different concept...) > Should i put the metadata for all disks on the hda > (hda4[0] for hda3, hda4[1] for hdb3, hda4[2] for hdc1) > or each metadata on its own disk > (hda4[0] for hda3, hdb4[0] for hdb3, hdc4[0] for hdc1) if you think seektime for meta-data updates, it is good to have meta-data on a different physical device than the associated data storage. but if one physical disk fails, you may lose the storage of one and the meta-data of an other drbd. oops. in that situation, you have to NOT just drbdadm up (or drbd start) the devices after you replaced the physical disk. you should # drbdadm attach all # drbdadm invalidate "name of device which storage was lost" # drbdadm connect all you will see a full sync for the drbd of which the meta data was lost (and got recreated), and a full sync for the drbd of which only the storage was lost, but the meta-data of which you just now invalidated. if you put (only) the meta-data on a software raid, you still need to invalidate it in case you lose the physical storage device associated with it. (btw, yet an other reason why I'd like to have a UUID stored in the meta data block as well as in some block on the physical storage device, when we have storage and meta-data on different devices.) Lars