BackupPC-users

[BackupPC-users] BackupPC and DRBD - My experience so far

2009-09-15 19:15:56
Subject: [BackupPC-users] BackupPC and DRBD - My experience so far
From: Chris Robertson <crobertson AT gci DOT net>
To: "General list for user discussion, questions and support" <backuppc-users AT lists.sourceforge DOT net>
Date: Tue, 15 Sep 2009 15:12:28 -0800
In short, it works for me.

Machine specs:

CPU : Intel Xeon X3320 (Quad Core @2.50GHz)
Memory: 8GB DDR2-667 ECC
Storage Controller: Adaptec 51645 (BIOS & Firmware 5.2-1 17380, driver 
1.1-5 2465)
Drives: 16 Seagate ST31000340NS (1TB ES.2) w/AN05 firmware
OS: CentOS 5.3

[root@archive-1 ~]# uname -a
Linux archive-1.gcimbs.net 2.6.18-128.7.1.el5 #1 SMP Mon Aug 24 08:21:56 
EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
[root@archive-1 ~]# rpm -q kmod-xfs
kmod-xfs-0.4-2
[root@archive-1 ~]# rpm -q drbd83
drbd83-8.3.2-6.el5_3
[root@archive-1 ~]# rpm -q kmod-drbd83
kmod-drbd83-8.3.2-6.el5_3

/data is an XFS file system (with an external journal) mounted 
(noatime,nodiratime,logdev=/dev/drbd1,logbufs=8,logbsize=262144) on top 
of  DRBD on  a RAID 6 setup provided by the fore mentioned Adaptec.

[root@archive-1 ~]# df -h /dev/drbd0
Filesystem            Size  Used Avail Use% Mounted on
/dev/drbd0            3.0T  984G  2.1T  33% /data
[root@archive-1 ~]# df -i /dev/drbd0
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/drbd0           1932728448 39835171 1892893277    3% /data

BackupPC Server Status

    * The servers PID is 23490, on host archive-1.gcimbs.net, version
      3.1.0, started at 2009-09-09 18:24.
    * This status was generated at 2009-09-15 14:08.
    * The configuration was last loaded at 2009-09-09 18:24.
    * PCs will be next queued at 2009-09-15 15:00.
    * Other info:
          o 0 pending backup requests from last scheduled wakeup,
          o 0 pending user backup requests,
          o 0 pending command requests,
          o Pool is 869.19GB comprising 12913308 files and 4369
            directories (as of 2009-09-15 13:27),
          o Pool hashing gives 2919 repeated files with longest chain 609,
          o Nightly cleanup removed 1038178 files of size 52.19GB
            (around 2009-09-15 13:27),
          o Pool file system was recently at 33% (2009-09-15 14:00),
            today's max is 33% (2009-09-15 09:00) and yesterday's max
            was 33%.

The observant will notice that my pool has grown significantly since 
August 27 
(http://article.gmane.org/gmane.comp.sysutils.backup.backuppc.general/20554).  
This is due to changing the way my biggest host (a web server) was 
backed up.  Suffice it to say, the change was not beneficial and has 
been reverted.

BackupPC: Host Summary

    * This status was generated at 2009-09-15 14:34.
    * Pool file system was recently at 33% (2009-09-15 14:00), today's
      max is 33% (2009-09-15 09:00) and yesterday's max was 33%.

Hosts with good Backups

There are 126 hosts that have been backed up, for a total of:

    * 500 full backups of total size 2562.94GB (prior to pooling and
      compression),
    * 1835 incr backups of total size 909.94GB (prior to pooling and
      compression).

The host information given in the linked email is still accurate.  I 
have since spun up a nearly identical server* on the far end of a GPON 
link.  The initial synchronization was allowed to transfer without a 
speed cap (and averaged around 600Mbit per second over a 12 hour 
period).  The latency between the two hosts is minimal...

[root@archive-1 ~]# ping -c10 archive-2.gcimbs.net
PING archive-2.gcimbs.net (66.223.232.56) 56(84) bytes of data.
64 bytes from 66.223.232.56: icmp_seq=1 ttl=64 time=0.450 ms
64 bytes from 66.223.232.56: icmp_seq=2 ttl=64 time=0.484 ms
64 bytes from 66.223.232.56: icmp_seq=3 ttl=64 time=0.459 ms
64 bytes from 66.223.232.56: icmp_seq=4 ttl=64 time=0.477 ms
64 bytes from 66.223.232.56: icmp_seq=5 ttl=64 time=0.491 ms
64 bytes from 66.223.232.56: icmp_seq=6 ttl=64 time=0.461 ms
64 bytes from 66.223.232.56: icmp_seq=7 ttl=64 time=0.434 ms
64 bytes from 66.223.232.56: icmp_seq=8 ttl=64 time=0.451 ms
64 bytes from 66.223.232.56: icmp_seq=9 ttl=64 time=0.478 ms
64 bytes from 66.223.232.56: icmp_seq=10 ttl=64 time=0.435 ms

--- archive-2.gcimbs.net ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9004ms
rtt min/avg/max/mdev = 0.434/0.462/0.491/0.018 ms

...even though they have more than a mile of physical separation.  I 
don't currently have good data as to the bandwidth utilization during 
backups (the DRBD config is set to limit it to 10M, which is about 
110Mbit/sec with TCP overhead), but the BackupPC_nightly and 
BackupPC_trashclean give an average 5Mbit/sec combined.  Over a 24 hour 
period the servers have passed nearly 80GB of data between them (78GB 
from the source, 2GB from the target).

There has been no discernible effect to the amount of time it takes to 
backup my hosts.

If you have any questions, or feel there is anything I was not clear 
about, feel free to ask.

Chris

* Its CPU is an Intel Xeon E3110 @3.0 GHz, with the other specs the 
same.  To be honest, the target does not need to be anything special (as 
long as it stays a target).  Even during the initial synchronization it 
was mostly idle.


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