Why is this seed not part if the "header" of the disk partition? Generated upon cache initiization.
> On Aug 12, 2014, at 9:44 AM, "ASF subversion and git services (JIRA)" > <[email protected]> wrote: > > > [ > https://issues.apache.org/jira/browse/TS-3000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14093633#comment-14093633 > ] > > ASF subversion and git services commented on TS-3000: > ----------------------------------------------------- > > Commit 83248169bbdaab383583fbb0b25f0916b18594c4 in trafficserver's branch > refs/heads/master from [~amc] > [ https://git-wip-us.apache.org/repos/asf?p=trafficserver.git;h=8324816 ] > > TS-3000: Add seed string for cache storage. > > >> Enable administrator control of seed strings for stripe assigment >> ----------------------------------------------------------------- >> >> Key: TS-3000 >> URL: https://issues.apache.org/jira/browse/TS-3000 >> Project: Traffic Server >> Issue Type: Improvement >> Components: Cache >> Reporter: Alan M. Carroll >> Assignee: Alan M. Carroll >> Fix For: 5.1.0 >> >> >> Objects are assigned to stripes based on a hash. The seed string for this >> hash is computed from properties of the storage. This means that if the >> storage is changed in any way, the hashing changes which disrupts assignment >> on all other stripes. >> An actual example is for a deployment that uses /dev/sdb .. /dev/sdx. If one >> of these disks fails (say /dev/sdm) then all of the other drives will "move >> down' at the next system restart which will in turn change the hash seed >> string for them which will make almost all of the cached objects on those >> drives inaccessible. Losing a single drive could wipe out most of the cache. >> This fix allows an administrator to specify the hash seed string in the >> storage.config file. The seed strings (and hence the resulting hash) can be >> kept consistent for a physical device even if the operating system >> assignment is changed. >> P.S. As a side note for Linux users, there are symlinks for raw disk devices >> in /dev/disk. These can be used in storage.config to avoid some of these >> problems. > > > > -- > This message was sent by Atlassian JIRA > (v6.2#6252)
