Need comments on ClearCase (3/5)

2007-12-25 9:26:00

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Jason Keltz

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Date: Fri, 31 Jan 1997 13:25:47 -0500

From: "Marc S. Gibian" <gibian@stars1.hanscom.af.mil>

To: cs911089@ariel.cs.yorku.ca

Subject: Re: Need comments on ClearCase

Boris,

>> My company is considering buying ClearCase. We have about 100 software

>> developers and document writers. Project group size is 3 - 6 persons. On

>> average we have 20 projects active. We have a mix of Sparc5, Sparc 20, and

>> some PC. We use Solaris 2.5.x on a few machines. Most of the rest of sparc

run

>> SunOs 4.1.x. The PCs run DOS, Win95, and WinNt.

If you are doing serious development, then ClearCase is one of the best

products

for appropriate configuration management! It IS complex, but it is worth

understanding and learning it because in the end it will save your hide and

time!

>> I would like to know what is the impact of using ClearCase:

>>

>> 1. Any additional work needed in system admin? Percentage increae in

workload?

It depends on how you define system admin vs. configuration management. In my

team, I am the lead system admin as well as the lead configuration manager so

things run together a bit. Even so, I do not spend all my time on these tasks

as

I am also a designer, developer, and technical lead (but, then, I AM a

consultant after all ;-)

>> 2. Hardware/resources requirements on Server, and Client stations.

Plan on dedicating hardware to your VOBs. Without knowning the number of files

you have to handle, its hard to guess at the number of VOBs. And you have more

engineers than I have to support, so I can only provide general suggestions.

You have enough people using this stuff that I strongly recommend setting up

your VOBs on a server class machine running some form of RAID. The added NFS

performance and data protection will provide the high availability you want in

a

VOB server. If you pick a platform that supports SMP, then you can start with

one or two processors and grow it as your performance demand increases. You

will

also want to give the VOB server a good shot of RAM to help. There are a number

of strategies when scaling up, such as using multiple VOB servers of less cost

rather than a fat central VOB server. Some of that is driven by the network you

have. If you have a switched ethernet, then multiple VOB servers makes more

sense than if you have a shared ethernet.

I prefer putting views on individual developer machines, thus distributing the

view server load. If they are in home directory trees, then you also ensure

backup of views. I make no special allowance for ClearCase related hardware for

clients, though make sure you have appropriate RAM and swap sizes for a

developer on them.

>> 3. Increase in network traffic.

I find that ClearCase doesn't pound your LAN, but if you already have a loaded

LAN, then ClearCase suffers badly. Since you're already in a development

environment, I tend to recommend switched ethernet and avoiding traversal of

the

backbone by individual projects (i.e. a compile should not hit the backbone,

with or without ClearCase.

>> 4. Any VOB backup/restore issue?

You need to treat the VOBs as databases as there is a database associated with

them. As such, you must use either a lock, backup, unlock or ClearCase 3.0's

semi-live backup capability. Otherwise, any backup tool reliable enough for

mission critical backups on the platform(s) you are using are fine. If you have

the $$$s for enough disk space to setup a mirror of your VOBs, then there are

tricks like locking, detaching the mirror, unlocking the live copy, continuing

work with the live copy of the mirror while backing up the frozen mirror, then

reattaching the frozen mirror and getting it re-synched. I don't have the

resources for this at my current customer, so you'll have to look through the

cciug archives for more details.

>> 5. Any file system management issue?

Nothing else that I can think of right now.

>> 6. Others.

>>

>> Comments from users also welcome.

Let me know if you have any other questions,

Marc

Marc S. Gibian

Telos Consulting Services phone: (617) 377-6350

PRISM/TFS email: gibian@stars1.hanscom.af.mil

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Date: Fri, 31 Jan 1997 10:39:43 -0500

From: Ravindra N Nemlekar <ravindra@airmail.hobl.lucent.com>

To: cs911089@ariel.cs.yorku.ca

Subject: Re: Need comments on ClearCase

We installed Clearcase a few weeks back and faced a lot

of problems in that.

More that 50% of the Clearcase software and database

should reside on the server machine itself (It does not

recognize NFS or automounts). The remaining may reside

on NFS mount points, but it should be insured that the

backups are properly syncronized, otherwise the admin

task is a headache.

The installation or admin manuals do not have all the

required info.

On Jan 30, 5:45pm , boris.xssc@fxap.xerox.com wrote ...

R>

R> Hi,

R>

R> My company is considering buying ClearCase. We have about 100 software

R> developers and document writers. Project group size is 3 - 6 persons. On

R> average we have 20 projects active. We have a mix of Sparc5, Sparc 20, and

R> some PC. We use Solaris 2.5.x on a few machines. Most of the rest of sparc

run

R> SunOs 4.1.x. The PCs run DOS, Win95, and WinNt.

R>

R> I would like to know what is the impact of using ClearCase:

R>

R> 1. Any additional work needed in system admin? Percentage increae in

workload?

R> 2. Hardware/resources requirements on Server, and Client stations.

R> 3. Increase in network traffic.

R> 4. Any VOB backup/restore issue?

R> 5. Any file system management issue?

R> 6. Others.

R>

R> Comments from users also welcome.

R>

R> Thanks,

R>

R> Boris.

R>


--
Indecision is the key to flexibility.

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