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Portal:Data Services/Admin/Wiki Replicas

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Revision as of 19:11, 16 November 2017 by imported>Quiddity (wikify (H2 as top-level section headers, rm underscores from links), copyedit)
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This page holds all the knowledge we have regarding Wiki Replicas for admins.

Service architecture by layers

Description of how the service is currently deployed.

Here is a general diagram of how things are:


Physical layer

This service is build on top of several physical servers:

  • labsdb1009.eqiad.wmnet
  • labsdb1010.eqiad.wmnet
  • labsdb1011.eqiad.wmnet

All servers are the same:

  • HP ProLiant DL380 Gen9
  • 16 CPU Intel(R) Xeon(R) CPU E5-2637 v3 @ 3.50GHz
  • 500GB RAM
  • 1 hard-disc in /dev/sda with 11.7 TiB (probaby RAID, using hpsa kernel driver)
  • 4 x 1GB ethernet interfaces (tg3)


  • isn't this information somewhere else?
  • no RAID status monitoring from userspace?

Storage layer

The service has a concrete storage configuration.

As seen by fdisk:

% sudo fdisk -l
Disk /dev/sda: 11.7 TiB, 12802299617280 bytes, 25004491440 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 262144 bytes / 2097152 bytes
Disklabel type: gpt
Disk identifier: 0933E022-348E-4F59-8F84-D4C3B32090BD

Device        Start         End     Sectors  Size Type
/dev/sda1      4096    78123007    78118912 37.3G Linux filesystem
/dev/sda2  78123008    93749247    15626240  7.5G Linux swap
/dev/sda3  93749248 25004490751 24910741504 11.6T Linux LVM

Disk /dev/mapper/tank-data: 11.6 TiB, 12754295455744 bytes, 24910733312 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 262144 bytes / 2097152 bytes

As seen by the LVM stack:

% sudo pvs
  PV         VG   Fmt  Attr PSize  PFree
  /dev/sda3  tank lvm2 a--  11.60t    0 
% sudo vgs
  VG   #PV #LV #SN Attr   VSize  VFree
  tank   1   1   0 wz--n- 11.60t    0 
% sudo lvs
  LV   VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  data tank -wi-ao---- 11.60t  

As seen by df:

% df -h
Filesystem             Size  Used Avail Use% Mounted on
udev                   252G     0  252G   0% /dev
tmpfs                   51G  4.1G   47G   8% /run
/dev/sda1               37G   11G   25G  31% /
tmpfs                  252G     0  252G   0% /dev/shm
tmpfs                  5.0M     0  5.0M   0% /run/lock
tmpfs                  252G     0  252G   0% /sys/fs/cgroup
/dev/mapper/tank-data   12T  6.5T  5.2T  56% /srv

All 3 servers should have more or less the same storage configuration.

DB layer

The databases in this service have a concrete layout/configuration.

Higher layers

Such as applications running on top, proxies, caches, et al.

Puppet deployment

The cluster is currently deployed using operations/puppet.git.

All the servers are given the labs::db::replica role, which currently include:

  • standard configs
  • mariadb packages + configs
  • ferm firewall + rules to allow the cluster to inter-comm
  • deployment of scripts, like maintain-views and friends

From production to wiki-replicas

Wiki databases from production are copied and sanitized to serve wiki-replicas.

Admin guide

Docs to perform common tasks related to this service. As detailed as possible.


Before this new cluster, we had an old cluster composed of physical servers: labsdb1001, labsdb1002 and labsdb1003.

At the time of this writing, the last standing server is labsdb1003, which is going down in December 2017.

See also