HP-UX and (RedHat) Linux

[Wim Rombauts]

Hello fellow administrators.

Since long, I have been an HP-UX administrator and I have been happy with it. We use it as our business-critical OS running 24x7, thus with mirroring, ServiceGuard, ...
MS Windows has been our secondary OS to run everything that is not available on HP-UX (which still seems to be a lot).

Now, because it is easier to find software to run on Linux, management wants a switch to Linux, mainly replacing HP-UX and taking away a few applications from windows.
Although I know that Linux is probably cheaper, is no longer a playground OS, and is matured enough to be an enterprise OS, I wander if it is matured enough to be our mission-critical OS.

Do some of you have extended expirience in Linux and HP-UX to see the difference, to know where to pay attention to, to know where the pitfalls are, what are the do's and don'ts. Why should we stay on HP-UX, or why should we certainly move to Linux.

For information : Until now, we never needed more than entry-level HP servers like the rp4440 or the rx6600. Two of them in a cluster with 2 to 3 processors in it, have allways been more than sufficient to run our complete business : Oracle RDBMS, datawarehouse, documentum, Oracle A.S., our finance software ... Maybe the sie of our servers matter in the choice of OS and hardware platform.

[whiteknight]

Hi Wim,

I agree with what you say, you may switch to Linux which is a cheaper.

Check this out to check why HPUX still a prefered choice for business value (TCO & ROI)http://h20338.www2.hp.com/hpux11i/cache/324574-0-0-225-121.html

Linux is catching up, the most importance you got a reliable hardware and provide good support structure, that is key to keep your business running on 24x7.

WK

please assign points

[Steven E. Protter · Accepted solution]

Shalom,

I'm an HP-UX CSA and an RHCE. Most of my day to day duties now involve Linux, though I support large systems and customers in HP-UX.

I find HP-UX to be a superior platform from the standpoint of reliabilty and stability. The OS and components are released in much better condition than equivalent releases for Red Hat.

I've run into particular stability problems with Red Hat Cluster Service, with memory leaks and other issues, making it difficult to certify an environment for HA that supports or Oracle DBMS.

Right now most of our customers go Linux with a predefined HA/Oracle solution that has been tested and slightly patched in our labs.

Our applictions that work with the db are all 32 bit. They run well on PA-RISC HP-UX, we are just beginning to test them on Itanium, with a simple 32 bit recompile (Aries was awful).

For large customers that benefit fro 64 bit address space, we still use and recommend HP-UX.

In essence, the right tool for the right job.

I would further challenge the assumption that Linux is less expensive. Red Hat's license fee's masked as support are very high, higher than the one time cost of purchasing HP-UX. The hardware is cheaper, but also less capable. Cost of ownerhip needs to be taken into account.

The full cost of the Red Hat Sattelite server, which is used to keep hosts up to date on rpms is very, very high compared to a software support contract from HP. I managed to save quite a lot of bucks adapting centos yum to update red hat machines from our own rpm repository.

Do:
1) Full cost benefit analysis, including long term cost of ownership.
2) Consider products like CentOS, which is a binary recompile of Red Hat and can be supported for near zero dollars per machine per year. Per incident support is the way t go, which you can get from HP or Red Hat.
3) Consider converting an rx6600 server to Linux. You may find surprising speed under this combination.

Dont:
1) Assume that you can move quickly or that 5 rx6600 systems can be replaced by 5 DL380 systems. It won't work like that.
2) Assume that cost of ownership with Linux will be lower. Oracle licenses per cpu and you may need MORE CPU's under Linux.
3) Don't assume that Red Hat Linux has matured enough. Their quality control is awful.

I'd be happy to elaborate if you have more specific questions. I'll check back on this thread.

SEP
RHCE
HP-UX CSA

[paolo barila]

Hi,


Security: Linux default installation disable "dangerous" services like telnet, ftp...

Oracle: from 10G version, Oracle is developed on Linux, (before it was on Solaris), that is: Oracle works best on Linux.


Pablo

[TwoProc]

Well, it's all a matter of you get what you pay for.

A Linux OS that costs $700 a year with support is NOT going to be nearly the same as an OS that cost $25K - $50K.

I administer both HP and Linux boxes, the HP boxes are database machines primarily and the Linux boxes are primarily middle-ware. Everytime a Linux box's file system has just cra**ed out on me and I call support and they calmy suggest that I "just reformat" the volume I count my blessings that HP db server doesn't have these issues.

The LAST time this came up I had both "arms" of the HP sales force (the intel server sales guy and the PA-Risc Itanium server sales guy) in my office. I needed a file to show them ( a file of statistics ), and my desktop machine (a Linux box) hung. We were AT THAT MOMENT discussing this very topic of Linux OS file systems just dying on us, though rarely, and how I thought it unlikely that I'd be willing to deploy a database on Linux because of this very problem. Well, I tried going to the console, and it was hung... so I tried to cold boot the box - and LO AND BEHOLD the box wouldn't boot! Since I was in a meeting, I switched to another office and had one of my sys admins look at my system while I was busy. At the end of the meetings, I spoke to the admin, and sure enough, file system was corrupt. Out of 30 servers or so, plus some desktops, we've lost probably 7 or 8 or so this way over 5 years. These are fully patched boxes! Want to know how many HPUX file systems I've lost due to file system corruption (excluding drive hardware failure) over the last FIFTEEN years? *None*, not a one - It's never happened. I'm not saying it never happens on HPUX to anyone, it does, I'm just saying that statistically, it's a whole different type of "reliability".

Other issues: system lockup and just needs reboot, or reboots itself. Linux: Probably as high as 50 times over 5 years. HPUX: I can count 3 events in my head since 93.

So, you'll find the Linux on Intel more like running Windows on Intel, and you'll find running HPUX like being on unarguably the least cool, most reliable, tough as nails, Unix OS out there.

Ever seen the "systems triangle" ?

.............Cheap
.........../.............\
........./.................\
......./.....................\
...../.........................\
Reliable--------------Fast

Of the 3 points of the triangle, pick two, you can *only* pick two.

Cheap and Reliable - not Fast
Cheap and Fast - not Reliable
Reliable and Fast - not Cheap!

[Heironimus]

The biggest point against Linux is that you're running on PC hardware. Very poor remote administration (BIOS settings, POST messages, etc.), less I/O bandwidth than enterprise systems, and a product cycle so fast that you'll have trouble buying certain components in a year or two. It also doesn't hold up well during hardware failures, things that would just make a 9000 mail you an alert can hard-lock a PC.

The most common clustering software on Linux seems to be Red Hat Cluster. It's very, very poor compared to ServiceGuard on HP-UX.

Ignite has its issues (like its reliance on NFS), but overall it's a good tool. You won't find anything quite like it for Linux, though there are a few tools that are slowly getting closer.

If you need to run Oracle (or other big-name apps) your options are usually limited to a short list of certified distributions because otherwise the vendor won't give you support. Red Hat is always on the list, but their quality control hasn't always been that good. I can't comment on the other common supported distributions.

Years ago I would have said that HP had better support, but the last time I worked on HP-UX their answer to every problem was "reboot the server" or "reinstall HP-UX". They rarely had anything to say about possible causes or preventive action for the future.

Linux systems can change most common kernel parameters, apply most patches, and reconfigure swap without rebooting. It also seems to be a little better at recovering after applications do bad things like use up all the swap. HP-UX is more likely to need a reboot for all of these things, plus booting an HP takes a lot longer than most Linux systems.

Most of my Linux systems just quietly keep running, and when I do have problems it's the same few machines almost every time. I have a number of servers that have been running for over a year since the last reboot. The application guys are happy because they never have to worry about anything but their apps.

The vast majority of the problems I've seen on Linux systems have been caused by hardware or inexperienced admins. The same applies to every other UNIX platform I've run, the only difference is how often I see them.

[Wim Rombauts]

Thanks already very much for willing to share your point of view. For everyone with an entry that shows first-hand expirience with HP-UX compared to Linux, there are 10 points waiting. I am not giving them now since that would make this thread look as solved and I hope some additional administrators are still willing to share there expirience.

[A. Clay Stephenson]

... and here is another area to which a great deal of thought should be given. I'll bet that you have loads of documented procedures on how to do maintenance tasks such as online disk replacement, OLAR replacement of HBA's/NIC's, SG package maintenance, user maintenance, printer maintenance, ... for HP-UX that have been throughly tested for HP-UX that will have to be re-invented for Linux. In my case, I know that I have some scripts/procedures that took me years to find all the wrinkles so than unplanned downtime approaches years.

You are also going to have to throughly test and debug all of your routine scripts for Linux as well --- especially if you choose to run that famous world's best shell. You can't even rely upon ksh because it too is different. Another area hat is often overlooked is customized printer interface files. HP's lpsubsystem ain't CUPS and there are significant differences.

I suppose that in order to do a fair apples to apples comparison, you would really have to run SG under Linux. The safe business approach would be to choose one application that you currently have under SG/HP-UX and migrate it as a test to Linux. That should be a relatively low-cost and low-risk approach and then you will have real-life data for your environment.

It's easy to do the high-level inspection to determine the initial hardware and OS cost differences. It's much more difficult to quantify the cost of downtime while you get to the same level of uptime that you currently experience under HP-UX.

[Wim Rombauts]

It looks like there are not going to be many more replies to this thread, so I assigned points and I will close it.
If someone would still like to add his comments, feel free, and if I get back to this thread, I will still assign points.