From Windows to Linux: Converting a Distributed Perforce Helix Infrastructure

From Windows to Linux:
Converting a Distributed
Perforce Helix
Infrastructure
David Foglesong
Senior Systems Software Engineer
Tableau Software

2
About Tableau Software
Tableau Software (NYSE: DATA) helps people see and
understand data. Tableau helps anyone quickly analyze,
visualize and share information. More than 35,000 customer
accounts get rapid results with Tableau in the office and on-
the-go. And tens of thousands of people use Tableau Public to
share data in their blogs and websites. See how Tableau can
help you by downloading the trial at www.tableau.com/trial.

3
Perforce At Tableau
 Started with CVS.
 Converted to Perforce in 2007 (on Windows).
 Infrastructure has evolved over time: One server > commit
+ replicas > commit + replicas + edge servers.
 650K+ changes, 900+ users, commit = 500G DB, edge =
800G DB.
 3 main dev offices, several smaller offices.

4
Why Change?
 Tableau product change from Win-only to Win/Mac to
Win/Mac/mobile (iOS/Android).
 Run other parts of build infrastructure (Artifactory,
ReviewBoard, OpenGrok) on Linux.
 Dev management wants “best” systems = performance,
stability, scalability.
 Perforce admins prefer Linux. 

5
Before
 1x commit server
 1x RO replica (backup and reporting)
 3x fwd replica (at main dev offices)
 Proxies at smaller dev offices.
 1x edge server (for build farm) + RO replica (backup)
 Brokers in front of everything.
 All on Windows.

7
After
 1x commit server
 2x RO replicas (backup and reporting)
 5x edge servers (3x for offices, 2x for build farm)
 5x RO replicas (backups for edge servers)
 Brokers in front of everything.
 All on Linux.
 Most in central data center.
 Proxies in dev offices.

9
Edge Servers vs. Forwarding Replicas
 Why switch offices to edge servers?
• Remote users (Palo Alto) see small lag on commands.
• Want to move most user data (db.have) off commit server – goal is to
have minimal (ideally none) connections from human users on commit
server.
 Move to cluster?
• Not at this time. Want to preserve option of moving edge server to dev
office if needed.

10
Process: Old vs. New
 Old way = checkpoint manipulation
• Either via scripts or p4migrate.
• Need to fix case inconsistencies in metadata. E.g.,
- //depot/source/foo.c#1 vs. //depot/SOURCE/bar.c#1
- User “bob” vs. user “BOB”.
• Transfer and convert archive files.

11
Process: Old vs. New
 New way = replication
• Create Linux replicas and edge servers connected to Windows commit
server.
• Use “verify –t” to transfer and convert archive files.
• Once everything but commit server is on Linux, failover commit server to
Linux RO replica.

12
Advantages/Disadvantages
 Advantages:
• Can do migration in stages.
 Disadvantages:
• Must run Linux servers with –C1 (case-insensitive) option.

13
Challenges
 RHEL7
 CVS2P4
 Platform specific references

14
Challenges – RHEL7
 IT standardized on RHEL7.
 RHEL7 uses systemd (vs. init scripts) to control services.
 Worked with John Halbig in support to create service unit
files for p4d (and p4p and p4broker), he created KB with
sample: http://answers.perforce.com/articles/KB/10832

15
Challenges – CVS2P4
 Original Perforce system created with cvs2p4 script.
 cvs2p4 works by using CVS change history to create
checkpoint to build DB files.
 The db entries refer to original CVS (RCS) archive files
stored in special “import” dir.
 CVS/RCS stores branches in the archive files, with revs like
1.1.1.1, but P4 uses separate files for branches.

16
Challenges – CVS2P4
 P4D resolves the CVS 1.1.1.1 branch revs OK, but “verify –t”
wouldn’t transfer them.
 Solution = Use smbclient + dos2unix to transfer the cvs2p4
import dir.
 This brought over ~70K changes, then used “verify –t” to
get rest.

17
Challenges – Platform specific entries
 Because we need to run in a mixed Win/Linux environment
during transition, can’t have platform specific entries
anywhere.
 Specific examples:
• Depot dir location.
• Trigger table entries.

18
Challenges – Depot dir location
 Win servers had “flat” P4ROOT layout where depot dirs were
nested in D:p4d dir. (e.g., D:p4ddepot)
 Short path length was partially to mitigate 260 char Win
max path issue.
 Didn’t want depots in P4ROOT on Linux, so set
“server.depot.root” configurable to put dirs in other location.

19
Challenges – Trigger table entries
 Single trigger table shared by all servers.
 As a result, can’t have:
• OS-specific paths in table.
• OS-specific binaries in table.
• OS-specific references in triggers.

20
Challenges – Trigger table paths
 Can’t use OS-specific paths in table.
 Solution = %serverroot% var + make sure tools (Perl,
Python, etc.) are present in base system path.
 Old =
C:python27python.exe C:bintrigger.py args
 New =
python2 %serverroot%/triggers/trigger.py args

21
Challenges – Trigger table binaries
 Can’t use OS-specific binaries in table.
 Solution = Wrappers and/or rename via client.
 Example: p4auth_ad.exe AD auth trigger.
 Old =
C:binp4auth_ad.exe args
 New =
%serverroot%/triggers/p4auth_ad.exe args
 Linux = p4auth_ad.pl gets synced as p4auth_ad.exe

22
Results
 Speed = Syncs, checkpoint/DB rebuild process, p4todb
rebuild are all faster on Linux servers.
 Load = Linux edge server for build farm handled 200+
“sync –f” at one time.

23
Summary
 Time
• It will take longer than expected.
 Effort
• It is easier than expected.
 Work with support.

24
References
 systemd = http://answers.perforce.com/articles/KB/10832
 P4Migrate = http://answers.perforce.com/articles/KB/2538
 P4Convert =
http://ftp.perforce.com/perforce/tools/p4convert/p4convert.
pdf

Thank you!
Contact: dfoglesong@tableau.com

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