[DRBD-user] drbd0: Digest integrity check FAILED.

Gregor Mosheh gregor at hostgis.com
Sun Aug 3 19:22:03 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Hey all. Last week I posted about repeated failures in the integrity 
checks, and am still having the problem. I have changed my configuration 
significantly since then in order to fix this, but it didn't change 
anything and this thing's never finished a full sync. I'd appreciate any 
further assistance in troubleshooting this.

Cabling, identical on both peers:
eth0 and eth1, both GigE
eth0 for Internet and LAN traffic
eth1 is a crossover to the other server, using 192.168 IPs
So that's a dedicated GigE link between the peers

Filesystem and underlying device:
2.4 TB partition, /dev/sda4
on a 3ware 9650 RAID-5
formatted with ext3

# ethtool --show-offload eth1
Offload parameters for eth1:
rx-checksumming: off
tx-checksumming: off
scatter-gather: off
tcp segmentation offload: off
udp fragmentation offload: off
generic segmentation offload: off

drbd.conf (selected bits)
   net     { cram-hmac-alg "sha1"; shared-secret "yeahright";
             data-integrity-alg "crc32c";
             max-buffers 1024;
   disk    { on-io-error pass_on; }
   syncer  { rate 50M; verify-alg crc32c; }
Internal metadata being used on both endpoints

Packet filters et al:
iptables allows all traffic on eth1, period.
after that are additional rules which should pertain
    only to other interfaces
no traffic shaping or monitoring, etc at the ethernet switch

General system load:
The system is under some significant load at all times. Load average 
ranges from 3 to 8 depending on the usage. LOTS of free/cache RAM

I also have a nearly-identical setup, which successfully syncs and 
verifies without a hitch. The configuration is identical to above, 
except as follows:
* 1.2 TB partition
* 3ware 9550s instead of 9650s
* no system load, since it's not yet deployed

Gregor Mosheh / Greg Allensworth, BS, A+
System Administrator
HostGIS cartographic development & hosting services

"Remember that no one cares if you can back up,
  only if you can restore." - AMANDA

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