I would rather use the machines efficiently than have to overbuy to support an arbitrarily defined standard. When you see a hardware standard in many companies, the reasoning they do it that way is just because they do it that way, not because anyone every sat down and thought it out to see if it makes sense. Maybe some analyst came in and said do it that way for some particular server and they just said let's do it for all of them. Or worse, someone read it somewhere and said, wow, let's just built them all this way with no understanding whatsoever of what they did or any idea of what they are trying to achieve. The most usual case I see for a good reason to run a mirrored OS is when you are using a NAS for all or a large percentage of your app data and the only local disk is OS.
I will argue with you that DCs are just another server with an app sitting on it. You don't, or at least you shouldn't be supporting them the same way because that will likely turn around and bite you. What do I mean by this? Many companies will have OS level admins and then App Admins and then AV Admins and then Monitoring Admins and then Software Delivery Admins and Security Audit Admins and this that and the other thing admins. DCs should only have Domain Admins and it should be a tiny group of 3-5 or so. Giving out rights and/or loading tools to allow others to manage those other components in every case that I have seen has greatly impacted the security of the environment. Usually though, the people just don't have a clue that it is that impacted. Obviously I know you and most of the folks on this list know this, this is nothing new to us. But I much rather push very hard that there is nothing standard about DCs in relation to other machines. Just make them standard within themselves. Usually in corporate load processes, at least the ones I have seen, someone generally manually configures the disk subsystem and then they load on a scripted/sysprepped/ghosted or hybrid load and off it goes. The underlying disk configuration really shouldn't be an issue at that point. All of the software is identical. A very common design I have seen is to use a high perf disk config in Data Centers where DCs will see serious use and then dropping all the way to a single Mirror for everything in a WAN site. Defining the standard to be mirror/mirror/0+1|10|5|mirror is usually going to be WAY overkill in most WAN sites though I have seen WAN sites with thousands of users and those, especially if they have local Exchange will want the Data Center config. joe -- O'Reilly Active Directory Third Edition - http://www.joeware.net/win/ad3e.htm -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, October 17, 2006 10:16 AM To: ActiveDir@mail.activedir.org Subject: RE: [ActiveDir] Seperating Database and logs on seperate disks "The latter - "we always have OS on a RAID1 set"." That's a fair argument - if the company has a hardware standard then it should be adhered to, if feasible. AD is just an app that sits on hardware as do other apps. Each app doesn't necessarily need a hardware spec all of its own. Standards lead to lower TCO so it's always worth striving for. [Simpler procurement, support, maintenance etc] Caveat: On the flip side, we all to get the best from our solutions and the corp standard may not achieve that optimal 'best'. I've never encountered a large company who'll happily change or allow exceptions re hardware standards without a very strong argument. My 2 penneth, neil -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Paul Williams Sent: 17 October 2006 14:31 To: ActiveDir@mail.activedir.org Subject: Re: [ActiveDir] Seperating Database and logs on seperate disks > What were the support reasons? Someone whined until they got the OS on > RAID-1 because that is the way "everyone" says they should do it or > another popular one is that is the way we "always" do it? The latter - "we always have OS on a RAID1 set". I've managed to swing RAID10 on the remaining 4 disks, and x64 and 32GB RAM. I can't get them (support folks) to take on support for pure RAID10. --Paul ----- Original Message ----- From: "joe" <[EMAIL PROTECTED]> To: <ActiveDir@mail.activedir.org> Sent: Tuesday, October 17, 2006 1:46 PM Subject: RE: [ActiveDir] Seperating Database and logs on seperate disks > What were the support reasons? Someone whined until they got the OS on > RAID-1 because that is the way "everyone" says they should do it or > another > popular one is that is the way we "always" do it? > > One of the issues is that most of the machines folks like to make into DCs > just don't have enough disk slots to have multiple spindles for the DIT if > you take up 4 for the OS and Logs. If you can get away with > mirror/mirror/6 > disk 0+1/10... Excellent, especially if x64 with sufficient RAM. If the > disk > counters start to show queuing on the DIT drive greater than what I > consider > heavy load (~2x#spindles) though I wouldn't hesistate to tear that down > and > make it into a single 10 disk RAID 0+1/10/5. With x64, as Paul indicated, > that generally shouldn't happen though unless you don't have enough memory > or possibly you have recently rebooted and are defrosting the cache. > > Mostly though, people should be looking at their own perf counters and > figuring out what they should be doing. Pay especially close attention to > Exchange GCs during the "morning rush" and the after lunch "rush", those > are > the two areas that tend to initially start showing pain. > > joe > > > -- > O'Reilly Active Directory Third Edition - > http://www.joeware.net/win/ad3e.htm > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Paul Williams > Sent: Tuesday, October 17, 2006 5:03 AM > To: ActiveDir@mail.activedir.org > Subject: Re: [ActiveDir] Seperating Database and logs on seperate disks > > Having discussed this quite a lot recently, I'll give you all an insight > into how I wanted to do it and how we are doing it (support reasons caused > me to be overridden): > > [want] 6 disks in a RAID10 array, with three volumes: OS, DIT & Logs, > SYSVOL > > and Scratch area. > [reallity] 2 disks in a RAID1 array for OS; 4 disks in a RAID10 array for > DIT & Logs, with another volume for SYSVOL and scratch. > > > Scratch contains the IFM directory (temporarily) and perf logs, etc. > > I agree with Joe 100% (probably because we have discussed this offline in > depth and he has moulded my opinions <g> ). Smaller environments don't > need > > to worry about it. Big environments need to think about it. Although, as > Joe mentions, it's rare you'll need much space for the log files. Even if > you provision a couple of hundred thousand users (which takes an hour or > two) you don't need much space for logs. Which is why I hate the 3x RAID1 > idea that is out there. Disks are cheap for sure, but that's still a > serious waste of two disks where they could be put to use for the DIT, > which > > is being slammed with read requests. > > Also remember that in smaller environments, or medium-sized environments > that have didicated DCs, a DL360 (or equivalent) which only has room for > two > > local disks, will happily run as a DC. A couple of the smaller projects > I've worked on in the past (~7,000 users) we used just this. Although in > some of those we had to use DL380s at some of the branches as they were > also > > running Exchange! : ( > > One other thing I'd like to say here, is if you do need to worry about > separating your disks, then you really should be looking at x64. You get > better throughput with x64 on disk and memory access, and you also have > the > ability to get all, or at least a chunk of, your DIT data (as in objects > that matter to your and your queries) into RAM. Those disk specs above > are > being implemented with x64 dual-core, dual-proc systems with 32GB of RAM > as > our standard DCs. > > (What can I say, I have a reasonable sized DIT ;-) > > (or so I'm told...) > > > --Paul > > ----- Original Message ----- > From: "joe" <[EMAIL PROTECTED]> > To: <ActiveDir@mail.activedir.org> > Sent: Tuesday, October 17, 2006 5:36 AM > Subject: RE: [ActiveDir] Seperating Database and logs on seperate disks > > >>I am surprised there aren't more responses to this. >> >> My personal opinion is that a vast majority of installations don't need >> to >> separate off the logs for perf. In fact, I have often recommended running >> everything on a single RAID 0+1/10/5 (partition logically if you want to >> say >> separate off the OS and the AD stuff) to get better perf than splitting >> logs >> and OS off onto their own disks. Especially in larger orgs for Exchange >> GCs >> that tried to follow the deployment docs and do mirror, mirror, mirror or >> mirror, mirror, 0+1 but didn't have enough disks to get a good 0+1. >> >> In every case that I have had to review DCs with questionable disk >> subsystem >> perf, the issues are always around the DIT while the disks for the OS and >> the Logs are snoozing with IOPS sitting there not being used that could >> have >> saved the DIT from getting sucked into the mud. Rebuilding the disk >> subsystem with all disks in one of the above configurations has >> alleviated >> the issues in every case. Whether RAID 5 or 0+1/10 is faster you will >> want >> to test with your own disk subystems (say with IOMETER), it seems to >> vary. > >> I >> have seen RAID-5 faster and I have seen on different machines 0+1/10 >> faster. >> >> >> A case I am aware of where the logs definitely were good off on their own >> and would have seriously impacted perf if they weren't was Eric's DIT >> experiment where he built a 2TB DIT but he was adding objects at a very >> high >> rate of speed constantly for quite a while so the logs were being beaten >> pretty well. >> >> joe >> >> >> -- >> O'Reilly Active Directory Third Edition - >> http://www.joeware.net/win/ad3e.htm >> >> >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of AD >> Sent: Monday, October 16, 2006 11:29 AM >> To: ActiveDir@mail.activedir.org >> Subject: [ActiveDir] Seperating Database and logs on seperate disks >> >> Is there any other reason other then performance to have the Active >> Directory log files and database on separate disks? >> >> Opinions are welcome. >> >> Thanks >> >> Yves >> List info : http://www.activedir.org/List.aspx >> List FAQ : http://www.activedir.org/ListFAQ.aspx >> List archive: http://www.activedir.org/ml/threads.aspx >> >> List info : http://www.activedir.org/List.aspx >> List FAQ : http://www.activedir.org/ListFAQ.aspx >> List archive: http://www.activedir.org/ml/threads.aspx > > List info : http://www.activedir.org/List.aspx > List FAQ : http://www.activedir.org/ListFAQ.aspx > List archive: http://www.activedir.org/ml/threads.aspx > > List info : http://www.activedir.org/List.aspx > List FAQ : http://www.activedir.org/ListFAQ.aspx > List archive: http://www.activedir.org/ml/threads.aspx List info : http://www.activedir.org/List.aspx List FAQ : http://www.activedir.org/ListFAQ.aspx List archive: http://www.activedir.org/ml/threads.aspx PLEASE READ: The information contained in this email is confidential and intended for the named recipient(s) only. 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