Question about virtualization.

Discussion in 'OT Technology' started by deusexaethera, Apr 29, 2008.

  1. deusexaethera

    deusexaethera OT Supporter

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    You know how most BIOSes have that switch to turn the CPU's virtualization functions on or off? Well, I was wondering, is there any benefit to shutting them off on a machine that will probably never run any virtual machines? Obviously they won't get used, but will leaving that feature turned on impact the physical machine's performance at all?
     
  2. Doomsday

    Doomsday XXX

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    stock,... no, it doesn't affect performance.
    if enabled and not used, it lies dormant or in a sleep state.

    in overclocking,.... disabling any unused CPU feature helps a lot.
    but note that the purpose of this is to make the CPU simple and easier to work with,... not because that feature has really a direct effect on performance.
     
  3. deusexaethera

    deusexaethera OT Supporter

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    Fair enough.

    In other news, the only physical machine left in my server rack now is the file server; all the rest of my old servers have been converted into VMs and are running on three VM servers. So much nicer and quieter and cooler now.
     
  4. Sexual Vanilla

    Sexual Vanilla New Member

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    Once you go VM, you don't look back.
     
  5. Sexual Vanilla

    Sexual Vanilla New Member

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    That is...until one of your VM servers crashes...you not only have to deal with a dead physical machine, but all of the VMs that were running on that server are gone as well.
     
  6. Doomsday

    Doomsday XXX

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    use VM backup solutions then
     
  7. crontab

    crontab (uid = 0)

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    this entirely depends on how it's setup...
     
  8. JayC71

    JayC71 Guest

    Not with ESX.... :naughty:
     
  9. crontab

    crontab (uid = 0)

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    AND a vmotion license, and shared storage, and its other requirements...
     
  10. Mike99TA

    Mike99TA I don't have anything clever to put here right now

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    I'm still not fully on the VM bandwagon...mostly because the vast majority of the servers I manage are database servers and a VM pretty much pukes with the IO/CPU/memory requirements we have (most of our DB servers are >32GB of memory, 16 processors, and anywhere from 500GB to 4TB of storage, not exactly VM material...

    We've migrated some app servers into VMs but they're noticeably slower which I don't like....definitely better than it was years ago but still not there yet, for me.
     
  11. crontab

    crontab (uid = 0)

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    Do those DB use all the resources all the time? I assume some are OLTP, some are OLAP, some OO, some not...

    At my previous place we had similar sized builds, but we HAD to get off of a dying platform, Tru64, and were looking to go virtual with Informix. The three contenders were IBM P-series with RHEL VPAR's or LPAR's, or whatever the hell they call it, RHEL on Vmware, and Solaris Zones. We were playing with an HP itanium at the time, but they didn't have the virt requirements for linux ready for our time frame.

    I left towards the end of this eval process, but it ultimately went to IBM P-series. All of the platforms blew the alpha out of the water, but that was relatively old. The slowest solution was Solaris product. The fastest was the Itanium. The VMware performed okay, 2nd slowest, but I doubt it would've been choosen given the tight limitations vm's have. The IBM was chosen for political BS. Scratch my back and I scratch yours. But it seems to be performing well from what I hear.
     
  12. Mike99TA

    Mike99TA I don't have anything clever to put here right now

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    Actually, almost every single one of our database is using a ton of resources. The servers that are running DBs that don't utilize full resources are actually running multiple databases so that we've roughly hit the limit with each server in terms of overall IO/Load/Memory/etc.
     
  13. deusexaethera

    deusexaethera OT Supporter

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    Yeah, that's what backups are for.
     
  14. deusexaethera

    deusexaethera OT Supporter

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    Oh yeah, if the physical machine is actually maxed out, then there's no reason to virtualize. The reason why I use it is because it decreases my rack's physical and electrical footprint, and most of my servers are low-usage anyway, so I can feasibly run 4+ of them on a single physical machine with dual quad-cores, 730GB SAS RAID, and 8GB of RAM.

    (and I have three of 'em. :wiggle:)
     
  15. crontab

    crontab (uid = 0)

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    Back to this comment. I agree. But I feel the bandwagon is mainly being driven why windows folks. There isn't much that vmware offers to UNIX in terms of HA that it cannot perform itself. Whereas it's another story with windows. It makes consolidation and HA for windows a piece of cake.
     
  16. deusexaethera

    deusexaethera OT Supporter

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    Taking into consideration what I said before, given your setup I'd rather have a bunch of little machines, each serving a single database. There's more overhead, but the little machines can be virtualized, which makes setting up a new one as simple as copying the VM's hard drive file.

    Not to mention, you can set up a VM cluster, wherein you have multiple physical machines each running the same set of VMs, and the copies of each VM are clustered together to share workload. That way, if one physical machine dies, instead of any of your databases going offline, the VMs hosting those databases just slow down instead, until the offline physical machine is fixed.
     
  17. JayC71

    JayC71 Guest

    Naturally. You may as well go all the way if you've got a datacenter.
     
  18. trouphaz

    trouphaz New Member

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    Wirelessly posted via wap.offtopic.com (Mozilla/2.0 (compatible; MSIE 3.02; Windows CE; PPC; 240x320) BlackBerry8703e/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/105)

    I'm not sold on virtualization on unix either. Vmware is great for windows since I've heard that windows can handle one app great, but you don't want to run multiple if you can avoid it. So virtualizing allows you to use up otherwise wasted resources as servers get more and more overpowered for smaller apps. Unix, on the other hand, is generally fine running all kinds of stuff with no issues.
     
  19. deusexaethera

    deusexaethera OT Supporter

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    That's a load of crap. Windows can run multiple server apps just fine, you just have to be more careful about installing multiple versions of libraries. I did it for years before I got my new servers.
     
  20. JayC71

    JayC71 Guest

    While I mostly agree, *nix does tend to be more stable in that you aren't patching the OS and rebooting it after the 2nd Tuesday of every month.
     
  21. Mike99TA

    Mike99TA I don't have anything clever to put here right now

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    We're on a quarterly patch cycle with our SLES servers right now and the vast majority of the quarterly patches don't require a reboot at all. With HP-UX we don't even do patch cycles anymore (the newest version we're running is 11.23 which has been out for who knows how many years). We will patch specific things that have stability issues or if we experience a problem but aside from that...

    I've rotated between Unix and Windows - every job I've had professionally I dealt with Unix but probably half of them with Windows... my last job I was the only admin for ~150 mixed unix/linux/windows servers and I can't begin to describe how many (negative) differences there was between managing the windows and Unix/Linux servers. My last day at the job...most of the Linux servers had been running for over a year without crashing or a reboot...all of our windows servers were on a weekly reboot cycle at monday 5am because if we didn't reboot them weird things started to happen :p I would say out of all the times I had to work after-hours at that job, 98% of it was working on the 6 exchange servers (I hate exchange so, so much, and I'm so glad I don't have to work with Windows at all at this job).
     
  22. AbortionSurvivor

    AbortionSurvivor Active Member

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    Sorry dude, but that isn't true.
    In a way, it's even MORE of a reason to virtualize.

    If your DB servers are constantly pinned and are the life blood of your company, then you WANT the protection of Virtualizing. -Specifically with VMWare's VMotion, High Availability, and Snapshots. Think what would happen if your precious server were to go down.

    Yes, Virtualizing takes some cycles away.
    However, with VMWare's ESXi the footprint left behind is TINY. Remember, VMW almost gets to bare metal.
    For those who don't know ESXi (Embedded)
    - Boots from USB. -Less then 64MB
    - Tiny footprint once in memory. TINY!
    - Never needs to read USB after server boots.
    - Has everything classic ESX has (Vmotion, HA, ..etc).
    - Only draw back is no Console OS. -*You do everything from GUI, no custom scripts.

    *Ok. The COS is still there, but it's "not supported". It's only there for serious professionals who know what they are doing. And don't ask me how to access the COS, cus i'm not tellin.
     
    Last edited: Apr 30, 2008
  23. AbortionSurvivor

    AbortionSurvivor Active Member

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    maybe is better question is if a few extra clock cycles is worth the HUGE uptime gain.
     
  24. crontab

    crontab (uid = 0)

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    Most db's already provide a form of reliable HA, hot - cold, hot - hot. Some prefer to even live one a cluster. One can use tran logs to go back in time as well. Some provide snapshot capability and some even provide their own storage management.

    All hypervisor's regardlesss of who it's from adds overhead. Even 3i. We saw no performance diff on a esx 3 and a esx3i machine. The vm's didn't run any faster nor slower. Unnecessary overhead is absolutely not acceptable in an environment that needs every once of resource, especially a db farm. VMWare is great for apps/db's/OS that can't do HA natively. Else it's a `gimmick`.
     
  25. Mike99TA

    Mike99TA I don't have anything clever to put here right now

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    I have to disagree with this. If our database server fails, one of the backup cluster nodes will immediately bring it back online - we get the HA (and faster HA at that then moving a VM to another host server) without the drop in IO that you get with virtualizing (CPU loss isn't anywhere near as bad as disk I/O in VMWare and other virtualization platforms from my experience).

    All of our DBs run on SAN disks that are secured to multiple systems, all of our DB servers are in clusters, and all of our DB servers are using things like failover bonded ethernet, etc.
     

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