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  • Where does a "Technical Programmer" fit in, and what does the title mean? [closed]

    - by Mike E
    Was: "What is a 'Technical Programmer'"? I've noticed in job posting boards a few postings, all from European companies in the games industry, for a "Technical Programmer". The job description was similar, having to do with tools development, 3d graphics programming, etc. It seems to be somewhere between a Technical Artist who's more technical than artist or who can code, and a Technical Director but perhaps without the seniority/experience. Information elsewhere on the position is sparse. The title seems redundant and I haven't seen any American companies post jobs by that name, exactly. One example is this job posting on gamedev.net which isn't exactly thorough. In case the link dies: Subject: Technical Programmer Frictional Games, the creators of Amnesia: The Dark Descent and the Penumbra series, are looking for a talented programmer to join the company! You will be working for a small team with a big focus on finding new and innovating solutions. We want you who are not afraid to explore uncharted territory and constantly learn new things. Self-discipline and independence are also important traits as all work will be done from home. Some the things you will work with include: 3D math, rendering, shaders and everything else related. Console development (most likely Xbox 360). Hardware implementations (support for motion controls, etc). All coding is in C++, so great skills in that is imperative. Revised Summarised Question: So, where does a programmer of this nature fit in to software development team? If I had these on my team, what tasks am I expecting them to complete? Can I ask one to build a new level editor, or optimize the rendering engine? It doesn't seem to be a "tools programmer" which focuses on producing artist tools, often in high-level languages like C#, Python, or Java. Nor does it seem to be working directly on the engine, nor a graphics programmer, as such. Yet, a strong C++ requirement, which was mirrored in other postings besides this one I quoted. Edited To Add As far as it being a low-level programmer, I had considered that but lacking from the posting was a requirement of Assembly. Instead, they tend to require familiarity with higher-level hardware APIs such as DirectX, or DirectInput. I wasn't fully clear in my original post. I think, however, that Mathew Foscarini has it right in his answer, so barring someone who definitely works with or as a "Technical Programmer" stepping in to provide a clearer explanation, I'll go with that. A generalist, which also fits the description of a more-technical-than-artist TA.

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  • How to write comments to explain the "why" behind the callback function when the function and parameter names are insufficient for that?

    - by snowmantw
    How should I approach writing comments for callback functions? I want to explain the "why" behind the function when the function and parameter names are insufficient to explain what's going on. I have always wonder why comments like this can be so ordinary in documents of libraries in dynamic languages: /** * cb: callback // where's the arguments & effects? */ func foo( cb ) Maybe the common attitude is "you can look into source code on your own after all" which pushes people into leaving minimalist comments like this. But it seems like there should be a better way to comment callback functions. I've tried to comment callbacks in Haskell way: /** * cb: Int -> Char */ func foo(cb) And to be fair, it's usually neat enough. But it gets into trouble when I need to pass some complex structure. The problem being partly due to the lack of type system: /** * cb: Int -> { err: String -> (), success: () -> Char } // too long... */ func foo(cb) Or I have tried this too: /** * cb: Int -> { err: String -> (), * success: () -> Char } // better ? */ func bar(cb) The problem is that you may put the structure in somewhere else, but you must give it a name to reference it. But then when you name a structure you're about to use immediately looks so redundant: // Somewhere else... // ResultCallback: { err: String -> (), success: () -> Char } /** * cb: Int -> ResultCallback // better ?? */ func foo(cb) And it bothers me if I follow the Java-doc like commenting style since it still seems incomplete. The comments don't tell you anything that you couldn't immediately see from looking at the function. /** * @param cb {Function} yeah, it's a function, but you told me nothing about it... * @param err {Function} where should I put this callback's argument ?? * Not to mention the err's own arguments... */ func foo(cb) These examples are JavaScript like with generic functions and parameter names, but I've encountered similar problems in other dynamic languages which allow complex callbacks.

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  • Dell VRTX - slow cluster shared storage

    - by NorbyTheGeek
    I have a brand new Dell VRTX box set up as a Failover Cluster running HA Hyper-V virtual machines. This is my first time setting up clustering, and my first time with one of these boxes, so I'm sure I've missed something. The virtual machines are experiencing high disk latency and bad performance when accessing their VHD(x) files located on a Cluster Shared Volume. The VRTX has 10 x 900 GB 10K SAS drives in RAID 6 configuration, and the VRTX has the redundant Shared PERC 8 controllers. Both blades have full access to the virtual disks. There are two M520 blades installed, each with 128 GB RAM. MPIO is configured for the PERC 8 controllers. Operating system on the blades is Server 2012 (NOT R2). The RAID 6 array is split into a small (8 GB) volume for cluster quorum witness and a large (6.5 TB) volume for a Cluster Shared Volume (mounted on the nodes as C:\ClusterStorage\Volume1) An example of slow disk access: logging into a Server 2012 VM and having Server Manager come up automatically. Disk access goes to 100%, with write speeds at 20 MB or so, read speeds of 500 KB or so, and Average Response Time of over 1000 ms, sometimes spiking at 4000-5000 ms or so. It's the latency that really worries me. Is there something specific I should look at in my configuration? It doesn't seem to matter whether I use VHD or VHDX, dynamic or static.

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  • Why datacenter water cooling is not widespread?

    - by MainMa
    From what I read and hear about datacenters, there are not too many server rooms which use water cooling, and none of the largerst datacenters use water cooling (correct me if I'm wrong). Also, it's relatively easy to buy an ordinary PC components using water cooling, while water cooled rack servers are nearly nonexistent. On the other hand, using water can possibly (IMO): Reduce the power consumption of large datacenters, especially if it is possible to create direct cooled facilities (i.e. the facility is located near a river or the sea). Reduce noise, making it less painful for humans to work in datacenters. Reduce space needed for the servers: On server level, I imagine that in both rack and blade servers, it's easier to pass the water cooling tubes than to waste space to allow the air to pass inside, On datacenter level, if it's still required to keep the alleys between servers for maintenance access to servers, the empty space under the floor and at the ceiling level used for the air can be removed. So why water cooling systems are not widespread, neither on datacenter level, nor on rack/blade servers level? Is it because: The water cooling is hardly redundant on server level? The direct cost of water cooled facility is too high compared to an ordinary datacenter? It is difficult to maintain such system (regularly cleaning the water cooling system which uses water from a river is of course much more complicated and expensive than just vacuum cleaning the fans)?

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  • Best Firewall product for hosting/housing environment?

    - by Raffael Luthiger
    I am searching for a firewall product (appliance or software) for an hosting/housing environment. The biggest problem is that the rules get very complex as more customers are behind the firewall. Some have only one server, others have a whole subnet. Some need NAT, some a VPN endpoint. Some customers want to only allow port http, others ssh as well. So the device needs to be able to support VLANs and it should be possible to group the rules per customer. Speed is another important point. And being able to manage redundant devices easily. I am searching for something that doesn't have all the extras like spam filter etc. I was searching a lot on the net but either they had all those extras as well (and with is an overloaded configuration interface) or they missed some of the features I need (e.g. VLAN). The VPN endpoint is not the an important criteria. We were thinking about a separate machine for it.

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  • cpanel dns only / rdns questions

    - by Clear.Cache
    I started getting IPs from ARIN directly, instead of the data center I'm colocated at. Now I have to start applying rdns myself for my clients upon request, instead of having the NOC at the DC do this. That is obvious, since I am in full control over the IP delegation and therefore have nameserver authority. The question is, how do I "create" ptr / rdns records for my clients? My current server uses Cpanel / WHM with ns1/ns2.mycompany.com I also applied those as dns nameservers in the ARIN IP's whois record. How do I create rdns for my clients? Should I install Cpanel DNS Only on a entirely separate server and use this method instead? http://layer1.cpanel.net/ If so, how can I seamlessly transition over the dns records to that new dns server, retaining my ns1/ns2.mycompany.com and their ns1 and ns2 IP addresses? Even more important: I have to change the ns1/ns2 IPs to the new ones I retrieve from ARIN. How can this be done, avoiding downtime during the dns transition? On a side note, would it be easier to just install Cpanel DNS Only on a dedicated server and just use dns1.mycompany.com and dns2.mycompany.com with their own dedicated ns1/ns2 IPs from ARIN - and utilize this dns server for customers who request rdns? Would this be a more viable solution than using our current ns1/ns2.mycompany.com Nameservers? Is Cpanel DNS Only a standalone software that does not require Cpanel/WHM on another server? Is it possible to have redundant dns servers setup using this software solely, ns1 on one server and ns2 on another? Thanks.

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  • Will this increase my Virtual private Server failing rate ?

    - by Spencer Lim
    Will this increase my Virtual private Server failing rate if i :- install Microsoft Window Server 2008 Enterprise install SQL server enterprise 2008 install IIS 7.5 install ASP.Net Mvc 2 install Microsoft Exchange << should live inside MWS2008 ? or standalone without OS? install Team foundation server << should live inside MWS2008 ? or standalone without OS? on one mini VPS with specification of DELL Poweredge R710 shared plan DDR3 ECC RAMs 16GB and -- 1GB for this VPS using DELL PERC 6i raid controller (this thing alone about 1.5k-2k) and the SAS HDD (15K RPM) (146GB) -- 33GB to this VPS each hdd is freaking fast over 300MB read / write possible with proper tuning the motherboard is a DELL and it has twin redundant PSU (870watt 85%eff) its running on Intel Xeon 5502 (Quad Core) x2 so about 8 physical proc (fairly share) is there any ruler to measure for this about one VPS can only install what what what service ? because of my resource is limited =.@ may i know if it is install in this way,maybe it seem like defeat the way of "VPS"... what will happen ? or any guideline on this issue (fully configuring the window server 2008 R2) ? Thx for reply

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  • How does enterprise failover, such as with google.com, actually work?

    - by Alex Regan
    We have a few fedora systems that are configured for web, FTP, and email services. We'd like to mirror these services, so that we can provide near 100% reliability for our users. I'm a fairly experienced Linux administrator, but don't have much experience with redundant systems. What is the best way to do this? How does google and amazon do it? Google.com resolves to multiple IP addresses, but if my local desktop caches one of the IPs that are unreachable, I'm going to get a failed connection message. How do they prevent that from happening? If one of their servers goes down, how is it automatically redirected to another system, without the end-user ever knowing it? I understand there are failover devices, but they're only for failing over the system itself, not a complete network. Let's say we have the worst-case scenario, such as my primary system becomes inaccessible. What are the fundamental components that are used on Linux systems to provide this capability? I'm looking for concepts, or approaches, not answers like "check out openstack". What are the actual pieces that make up the solution? What has to be done to implement this capability? Hopefully my question is clear. I'd like to know what the pieces are that make up a failover system and what approach is taken by successful organizations that implement it. Thanks again, Alex

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  • Rack layout for future growth

    - by bleything
    We're getting ready to move to a new colo facility and I'm designing the rack layout. While we have a full rack, we only have 12U worth of hardware right now: 1x 1U switch 7x 1U servers 1x 2U server 1x 2U disk shelf The colo facility requires us to front-mount the switch and use a 1U brush strip, so we'll be using a total of 13U of space. Regarding growth, I'm reasonably sure we'll be adding another 4U in servers, 1-2U of network gear, and 2-4U of storage in the mid-term. Specific questions I'm hoping to get help with: where should I mount the switch? the LEDs are on top... should I group the servers by function with space for adding new machines? as an alternative, should I group servers based on whether they are production or staging? where in the rack should I start? in the middle? at the top? at the bottom? equally spaced? Here's a silly little ASCII diagram of what I'm thinking right now. Please feel free to tear my design apart, I've really no idea what I'm doing :) Any advice is very welcome. edit: to be clear, the colo is providing redundant power with UPS and generator, so that's why there's no power gear in the plan, except for the 0U PDU that I didn't diagram. 42 | -- switch ---------------------- 41 | -- brush strip ----------------- 40 | ~~ reserved for second switch ~~ 39 | ~~ reserved for firewall ~~~~~~~ 38 | 37 | -- admin01 --------------------- 36 | 35 | -- vm01 ------------------------ 34 | -- vm02 ------------------------ 33 | ~~ reserved for vm03 ~~~~~~~~~~~ 32 | ~~ reserved for vm04 ~~~~~~~~~~~ 31 | ~~ reserved for vm05 ~~~~~~~~~~~ 30 | 29 | -- web01 ----------------------- 28 | -- web02 ----------------------- 27 | ~~ reserved for web03 ~~~~~~~~~~ 26 | ~~ reserved for web04 ~~~~~~~~~~ 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | -- db01 ------------------------ 15 | +- disks ----------------------+ 14 | +------------------------------+ 13 | ~~ reserved for more ~~~~~~~~~~~ 12 | ~~ db01 disks ~~~~~~~~~~~~~~~~~~ 11 | 10 | +- db02 -----------------------+ 9 | +------------------------------+ 8 | ~~ reserved for db02 ~~~~~~~~~~~ 7 | ~~ disks ~~~~~~~~~~~~~~~~~~~~~~~ 6 | ~~ reserved for more ~~~~~~~~~~~ 5 | ~~ db02 disks ~~~~~~~~~~~~~~~~~~ 4 | 3 | 2 | 1 |

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  • iSCSI SAN Implementation with several ESXi hosts and two Equallogic SANs

    - by Sergey
    I work for a small state college. We currently have 4 ESXi hosts (all made by Dell), 2 EqualLogic SANs (PS4000 and PS4100) and a bunch of old HP Procurve switches. The current setup is very far from being redundant and fast so we want to improve it. I read several threads but get even more confused. The Procurve Switches are 2824. I know they don't support Jumbo Frames and Flow Control at the same time, but we have plans to upgrade to something like Procurve 3500yl. Any suggestions? I heard Dell Powerconnects 6xxx are pretty good but I'm not sure how they compare to HPs. There will be a 4-port Etherchannel (Link Aggregation) between the switches, and all control modules on SAN will be connected to different switches. Is there anything that will make the setup better? Are there better switches then Procurves 3500yl that cost less than 5k? What kind of bandwidth can I expect between ESXi hosts (they will also be connected to 2824 with multiple cables) and SANs?

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  • Intermittent unavailability of an instance in a failover cluster while a standby node is offline in

    - by Emil Fridriksson
    Hi everyone. I've got a small failover cluster that I run for the websites my company has. During a RAM upgrade of the standby server, our websites started to show errors about not being able to access the database server. I verified that the instance was indeed up and the server accessable via remote desktop. I also tried a SQL connection to it and it worked, but that might have been after it became available again. This happened on and off until we were able to roll back the hardware changes that were in progress on the standby server and we were able to bring it back up. There was nothing of interest in the SQL Server log, but there is a continous log for the whole duration of the problem, so there was no restart of the SQL Server service. The event viewer is of more interest, since it shows events relating to the heartbeat network card, but I don't know how that would affect the availability of the server, since the standby node is offline. I'd appreciate any help you can provide, it's not very redundant if the setup depends on the standby server being up. :) Here are the event logs from the time of the problem, I include all of them since I can't seem to see what could possibly be the cause of the problem. Event log: http://hlekkir.com:800/htmltable.htm

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  • Using mixed disks and OpenFiler to create RAID storage

    - by Cylindric
    I need to improve my home storage to add some resilience. I currently have four disks, as follows: D0: 500Gb (System, Boot) D1: 1Tb D2: 500Gb D3: 250Gb There's a mix of partitions on there, so it's not JBOD, but data is pretty spread out and not redundant. As this is my primary PC and I don't want to give up the entire OS to storage, my plan is to use OpenFiler in a VM to create a virtual SAN. I will also use Windows Software RAID to mirror the OS. Partitions will be created as follows: D0 P1: 100Mb: System-Reserved Boot D0 P2: 50Gb: Virtual Machine VMDKs for OS D0 P3: 350Gb: Data D1 P1: 100Mb: System-Reserved Boot D1 P2: 50Gb: Virtual Machine VMDKs for OS D1 P3: 800Gb: Data D2 P1: 450Gb: Data D3 P1: 200Gb: Data This will result in: Mirrored boot partition Mirrored Operating system Mirrored Virtual machine O/S disks Four partitions for data In the four data partitions I will create several large VMDK files, which I will "mount" into OpenFiler as block-storage devices, combined into three RAID arrays (due to the differing disk sizes) In effect, I'll end up with the following usable partitions SYSTEM 100Mb the small boot partition created by the Windows 7 installer (RAID-1) HOST 50Gb the Windows 7 partition (RAID-1) GUESTS 50Gb Virtual machine Guest VMDK's (RAID-1) VG1 900Gb Volume group consisting of a RAID-5 and two RAID-1 VG2 300Gb Volume group consisting of a single disk On VG1 I can dynamically assign storage for my media, photographs, documents, whatever, and it will be safe. On VG2 I can dynamically assign storage for my data that is not critical, and easily recoverable, as it is not safe. Are there any particular 'gotchas' when implementing a virtual OpenFiler like this? Is the recovery process for a failing disk going to be very problematic? Thanks.

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  • Kerberos service on win2k dc will not start following disk failure

    - by iwilson68
    Hi, I have a win2k (mixed mode domain) with 4 DCS. One of these also acts an exchange 2000 server which uses 2 logical volumes from an MSA 2000 array. AD etc is stored on local drives. We experienced a problem last week when the raid array fell back to a redundant controller and this temporarily meant that the two logical drives were not visible to the server for around 5 minutes and a couple of reboots. The log records these Events as Type: Warning Event Source: Disk Event Category: None Event ID: 51 Date: 06/11/2009 Time: 11:46:23 User: N/A Computer: server1 Description: An error was detected on device \Device\Harddisk1\DR1 during a paging operation. Following these problems, the server “kerberos Key Distribution” service refuses to start with an “error.31 a device attached to the system is not functioning”. All other automatic start services (including net logon) are running and there are no DNS issues etc. All devices are also functioning but the two logical MSA disks are now numbered in the Windows Disk Management MMC as 2 and 4 and I suspect that they may have previously been identified as disks 1 & 2 and perhaps windows still sees this as an ongoing failure?? Replication has not been affected but obviously there are many audit failures in the security log relating to users and workstations presumably linked to the Kerberos issue. Attempting to manually start the kerberos service generates the following in the System Log. Event Type: Error Event Source: Service Control Manager Event Category: None Event ID: 7023 Date: 09/11/2009 Time: 09:46:55 User: N/A Computer: Server1 Description: The Kerberos Key Distribution Center service terminated with the following error: A device attached to the system is not functioning. DCDIAG passes all tests except “Advertising” and “Services” which I believe relate directly to the failure of Kerberos only. Any advice would be appreciated.

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  • Pitfalls to using Gluster as a home/profile directory server?

    - by Bart Silverstrim
    I was asking recently about options for divvying up access to file servers, as we have a NAS solution that gets fairly bogged down when our users (with giant profiles, especially) all log in nearly simultaneously. I ran across Gluster and it looks like it can cluster different physical storage media into a single virtual volume and share it out like a virtual NAS from the client perspective and it support CIFS. My question is whether something like this would be feasible to use for home and profile directories in an active directory environment. I was worried about ACL's, primarily, as I didn't think CIFS was fine-grained enough to support NTFS permissions and it didn't look like Gluster exports those permission levels, just the base permissions for basic file sharing. I got the impression that using Gluster would allow for data to be redundant across multiple servers and would speed up access to the files under heavy load, while allowing us to dynamically boost storage capacity by just adding another server and telling Gluster's master node to add that server. Maybe I'm wrong with my understanding of it though. Anyone else use it or care to share how feasible this is?

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  • How to set up multiple DNS servers on an intranet

    - by Brent
    We have an Active Directory network, with a mixture of Windows DNS, linux BIND servers, and want to use OpenDNS as our external DNS provider. I am wondering What is the best way to set up these servers (regarding forwarders, recursion, etc.)? Active Directory is our main internal DNS for our domain, and has 3 redundant servers. DHCP and all our servers use these as their DNS servers. Then we have a legacy AD server from an old network that is still authoritative for a bunch of domains. Finally, we have a couple of Linux Bind servers that are authoritative for a bunch of websites we host. Should our main AD servers point to our legacy AD server, which points to one of our BIND servers, which points to the other BIND server, which finally points out to openDNS? Or should our main AD servers point to all of these directly? - or is there a better option? What happens if a domain is listed in 2 places? Does DNS process the forwarders in order? What about root servers - if I want to use OpenDNS for "everything else", do I just list them as the last forwarders, and delete the root servers from all my DNS servers? How does recursion work - in this scenario, should I be using recursion or not?

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  • Why is a FLAC encoded from a decoded MP3 bigger than the MP3?

    - by Ryan Thompson
    To be more precise than in the title, suppose I have a MP3 file that is 320 kbps. If I decompress it, then logically, all the data except for roughly 320 kilobits out of each second of audio should be redundant data, able to be compressed away. So, when I encode the decompressed file to FLAC, or any other lossless codec, why is it so much larger? On a related note, is it theoretically possible to losslessly recover the source mp3 audio from a decompressed wav? (I know the mp3 itself is lossy. I'm asking if it's possible to re-encode without any further loss.) EDIT: Let me clarify the related question, and the rationale behind it. Suppose I have a wav that was decompressed from an MP3 file (and assume I don't have the mp3 itself for some reason). If I don't want to lose any more quality, I can re-encode it with FLAC or any other lossless encoder and get a larger file just to maintain the same quality. Or, I can re-encode it to mp3 again and get the same size as the original but lose more data. Obviously, neither of these cases is ideal. I can either have the original size or the original quality, but not both (I mean the quality of the original mp3, not the original lossless source). My question is: Can we get both? Is it theoretically possible to recover the lossy compressed data from the lossy decompressed data, without losing even more? If it is possible, I could imagine a lossless compression algorithm that compresses the audio with FLAC. Then it also scans the audio for any signs of previous lossy compression, and if detected, recompresses it losslessly to the original lossy file. Then it keeps whichever file is smaller.

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  • Getting started with webserver clustering.

    - by Ernie
    I work for a small ISP, and we host about 250 domains and all the stuff that goes along with that: DNS, mail, spam filtering, and backups. Currently, we have separate DNS servers (two of them) and mail servers (outgoing mail is actually on the secondary DNS server, but was previously on its own server). In the past, this was done as an insurance measure. The last thing we need is for some doofus (usually yours truly) to hose a server, taking out DNS and mail right along with it, or for spammers to jam our incoming SMTP server, preventing outgoing mail from being sent too. In the past, this was a problem, and our servers were set up the way they are now to combat it. However, clustering solutions like Sun's Cobalt RAQ (in days of olde) and Virtualmin appear to cater to an all-in-one approach, then deal with failures through redundant servers. I have avoided this thus far, but we've been using Virtualmin on our web server for a while now, and I'd like to expand into using it for a high availability cluster. Our networking partner has recently built a datacenter that has eliminated all of our other bugaboos like network, cooling, and power issues, so now the only thing left to go wrong is me hosing a server, which happened earlier this month. One of the bigger reasons we've avoided going this route is because our hardware requirements aren't particularly high. One server easily handles all the sites we host (most of them are flat sites). Also, load-balancing routers tend to be expensive and complicated. All that I'm really expecting to do is building a two-node cluster for redundancy so that when I hose a server (however rare that might be), we're not out for 8-12 hours while I rebuild it. What I need to know is how to get started, and if I'm really in a position to bother with this kind of thing at all.

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  • APC Smart UPS network shutdown issue

    - by Rob Clarke
    Here is a bit about our setup: We have 2x Smart-UPS RT 6000 XL units with network management cards We are running Powerchute from a network server Powerchute is connected to the management cards of both UPSs UPSs are set to do a graceful shutdown via Powerchute when the battery duration is under 20 minutes We also have a command file that runs with Powerchute Although our setup is redundant we do not have an equal load on each server due to APC switches for single power devices The problem is that as we do not have an equal load on each server the batteries drain at different rates. This means that the UPSs both get to the specified low battery duration at completely different times. The problem here is that UPS 1 may have run down to 5 minutes and is in desperate need of initiating a Powerchute shutdown - UPS 2 still has 25 minutes of runtime so no shutdown is initiated. Consequently UPS 1 goes down and takes all the servers with and then shuts down UPS 2 as well! What we need to happen are 1 of either 2 things: Powerchute initiates the shutdown as soon as either UPS reaches the 20 minutes low battery duration setting - and doesnt wait for both The UPS with the heavier load expends its entire battery but does not shutdown both UPSs and lets the load be switched across to the UPS that still has runtime remaining. That way when the UPS that still has runtime reaches its low battery duration it can proceed with the graceful shutdown via Powerchute. Hope that makes sense, any help is greatly appreciated!

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  • AuthBasicProvider: failover not working when the first LDAP is down?

    - by quanta
    I've been trying to setup redundant LDAP servers with Apache 2.2.3. /etc/httpd/conf.d/authn_alias.conf <AuthnProviderAlias ldap master> AuthLDAPURL ldap://192.168.5.148:389/dc=domain,dc=vn?cn AuthLDAPBindDN cn=anonymous,ou=it,dc=domain,dc=vn AuthLDAPBindPassword pa$$w0rd </AuthnProviderAlias> <AuthnProviderAlias ldap slave> AuthLDAPURL ldap://192.168.5.199:389/dc=domain,dc=vn?cn AuthLDAPBindDN cn=anonymous,ou=it,dc=domain,dc=vn AuthLDAPBindPassword pa$$w0rd </AuthnProviderAlias> /etc/httpd/conf.d/authz_ldap.conf # # mod_authz_ldap can be used to implement access control and # authenticate users against an LDAP database. # LoadModule authz_ldap_module modules/mod_authz_ldap.so <IfModule mod_authz_ldap.c> <Location /> AuthBasicProvider master slave AuthzLDAPAuthoritative Off AuthType Basic AuthName "Authorization required" AuthzLDAPMemberKey member AuthUserFile /home/setup/svn/auth-conf AuthzLDAPSetGroupAuth user require valid-user AuthzLDAPLogLevel error </Location> </IfModule> If I understand correctly, mod_authz_ldap will try to search users in the second LDAP if the first server is down or OpenLDAP on it is not running. But in practice, it does not happen. Tested by stopping LDAP on the master, I get the "500 Internal Server Error" when accessing to the Subversion repository. The error_log shows: [11061] auth_ldap authenticate: user quanta authentication failed; URI / [LDAP: ldap_simple_bind_s() failed][Can't contact LDAP server] Did I misunderstand?

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  • Reason for perpetual dynamic DNS updates?

    - by mad_vs
    I'm using dynamic DNS (the "adult" version from RFC 2136, not à la DynDNS), and for a while now I've been seeing my laptops with MacOS 10.6.x churning out updates about every 10 seconds. And seemingly redundant updates at that, as the IP is more or less stable (consumer broadband). I don't remember seeing that frequency in the (distant...) past. The lowest time-to-live that MacOS pushes on the entries is 2 minutes, so I have no clue what's going on. ... Jan 12 13:17:18 lambda named[18683]: info: client 84.208.X.X#48715: updating zone 'dynamic.foldr.org/IN': deleting rrset at 'rCosinus._afpovertcp._tcp.dynamic.foldr.org' SRV Jan 12 13:17:18 lambda named[18683]: info: client 84.208.X.X#48715: updating zone 'dynamic.foldr.org/IN': adding an RR at 'rCosinus._afpovertcp._tcp.dynamic.foldr.org' SRV Jan 12 13:17:26 lambda named[18683]: info: client 84.208.X.X#48715: updating zone 'dynamic.foldr.org/IN': deleting rrset at 'rcosinus.dynamic.foldr.org' AAAA ... Additionally, I can't find out what triggers the updates on the laptop-side. Is this a known problem, and how would I go about debugging it? One of the machines is freshly purchased and installed. The only "major" change was installation of the Miredo client for IPv6/Teredo, but even disabling it didn't make a change (except that AAAA records are no longer published).

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  • How can I manage AWS VPC ssh access accounts and keys across multiple instances?

    - by deitch
    I am setting up a standard AWS VPC structure: a public subnet some private subnets, hosts on each, ELB, etc. Operational network access will be via either an ssh bastion host or an openvpn instance. Once on the network (bastion or openvpn), admins use ssh to access the individual instances. From what I can tell all of the docs seem to depend on a single user with sudo rights and a single public ssh key. But is that really best practice? Isn't it much better to have each user access each host under their own name? So I can deploy accounts and ssh public keys to each server, but that rapidly gets unmanageable. How do people recommend managing user accounts? I've looked at: IAM: It doesn't like like IAM has a method for automatically distributing accounts and ssh keys to VPC instances. IAM via LDAP: IAM doesn't have an LDAP API LDAP: set up my own LDAP servers (redundant, of course). Bit of a pain to manage, still better than managing on every host, especially as we grow. Shared ssh key: rely on the VPN/bastion to track user activities. I don't love it, but... What do people recommend? NOTE: I moved this over from accidentally posting in StackOverflow.

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  • APC Smart UPS network shutdown issue

    - by Rob Clarke
    Here is a bit about our setup: We have 2x Smart-UPS RT 6000 XL units with network management cards We are running Powerchute from a network server Powerchute is connected to the management cards of both UPSs UPSs are set to do a graceful shutdown via Powerchute when the battery duration is under 20 minutes We also have a command file that runs with Powerchute Although our setup is redundant we do not have an equal load on each server due to APC switches for single power devices The problem is that as we do not have an equal load on each server the batteries drain at different rates. This means that the UPSs both get to the specified low battery duration at completely different times. The problem here is that UPS 1 may have run down to 5 minutes and is in desperate need of initiating a Powerchute shutdown - UPS 2 still has 25 minutes of runtime so no shutdown is initiated. Consequently UPS 1 goes down and takes all the servers with and then shuts down UPS 2 as well! What we need to happen are 1 of either 2 things: Powerchute initiates the shutdown as soon as either UPS reaches the 20 minutes low battery duration setting - and doesnt wait for both The UPS with the heavier load expends its entire battery but does not shutdown both UPSs and lets the load be switched across to the UPS that still has runtime remaining. That way when the UPS that still has runtime reaches its low battery duration it can proceed with the graceful shutdown via Powerchute. Hope that makes sense, any help is greatly appreciated!

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  • hosts.deny not blocking ip addresses

    - by Jamie
    I have the following in my /etc/hosts.deny file # # hosts.deny This file describes the names of the hosts which are # *not* allowed to use the local INET services, as decided # by the '/usr/sbin/tcpd' server. # # The portmap line is redundant, but it is left to remind you that # the new secure portmap uses hosts.deny and hosts.allow. In particular # you should know that NFS uses portmap! ALL:ALL and this in /etc/hosts.allow # # hosts.allow This file describes the names of the hosts which are # allowed to use the local INET services, as decided # by the '/usr/sbin/tcpd' server. # ALL:xx.xx.xx.xx , xx.xx.xxx.xx , xx.xx.xxx.xxx , xx.x.xxx.xxx , xx.xxx.xxx.xxx but i am still getting lots of these emails: Time: Thu Feb 10 13:39:55 2011 +0000 IP: 202.119.208.220 (CN/China/-) Failures: 5 (sshd) Interval: 300 seconds Blocked: Permanent Block Log entries: Feb 10 13:39:52 ds-103 sshd[12566]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.119.208.220 user=root Feb 10 13:39:52 ds-103 sshd[12567]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.119.208.220 user=root Feb 10 13:39:52 ds-103 sshd[12568]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.119.208.220 user=root Feb 10 13:39:52 ds-103 sshd[12571]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.119.208.220 user=root Feb 10 13:39:53 ds-103 sshd[12575]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.119.208.220 user=root whats worse is csf is trying to auto block these ip's when the attempt to get in but although it does put ip's in the csf.deny file they do not get blocked either So i am trying to block all ip's with /etc/hosts.deny and allow only the ip's i use with /etc/hosts.allow but so far it doesn't seem to work. right now i'm having to manually block each one with iptables, I would rather it automatically block the hackers in case I was away from a pc or asleep

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  • Probability of Blade Chassis Failure

    - by ChrisZZ
    In my organisation we are thinking about buying blade servers - instead of rack servers. Of course technology vendors also make them sound very nice. A concern, that I read very often in different forums, is, that there is a theoretical possibility of the server chassis going down - which would in consequence take all the blades down. That is due to shared infrastructure. My reaction on this probability would be to have redundancy and by two chassis instead of one (very costly of course). Some people (including e.g. HP Vendors) try to convince us, that the chassis is very very unlikely to fail, due to many redundancies (redundant power supply, etc.). Another concern on my side is, that if something goes down, spare parts might be required - which is difficult in our location (Ethiopia). So I would ask to experienced administrators, that have managed blade server: What is your experience? Do they go down as a whole - and what is the sensible shared infrastructure, that might fail? That question could be extended to shared storage. Again I would say, that we need two storage units instead of only one - and again the vendors say, that this things are so rock solid, that no failure is expected. Well - I can hardly believe, that such a critical infrastructure can be very reliable without redundancy - but maybe you can tell me, whether you have successfull blade-based projects, that work without redundancy in its core parts (chassis, storage...) At the moment, we look at HP - as IBM looks much to expensive... thanks a lot best regards Christian

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  • Multiple LDAP servers with mod_authn_alias: failover not working when the first LDAP is down?

    - by quanta
    I've been trying to setup redundant LDAP servers with Apache 2.2.3. /etc/httpd/conf.d/authn_alias.conf <AuthnProviderAlias ldap master> AuthLDAPURL ldap://192.168.5.148:389/dc=domain,dc=vn?cn AuthLDAPBindDN cn=anonymous,ou=it,dc=domain,dc=vn AuthLDAPBindPassword pa$$w0rd </AuthnProviderAlias> <AuthnProviderAlias ldap slave> AuthLDAPURL ldap://192.168.5.199:389/dc=domain,dc=vn?cn AuthLDAPBindDN cn=anonymous,ou=it,dc=domain,dc=vn AuthLDAPBindPassword pa$$w0rd </AuthnProviderAlias> /etc/httpd/conf.d/authz_ldap.conf # # mod_authz_ldap can be used to implement access control and # authenticate users against an LDAP database. # LoadModule authz_ldap_module modules/mod_authz_ldap.so <IfModule mod_authz_ldap.c> <Location /> AuthBasicProvider master slave AuthzLDAPAuthoritative Off AuthType Basic AuthName "Authorization required" AuthzLDAPMemberKey member AuthUserFile /home/setup/svn/auth-conf AuthzLDAPSetGroupAuth user require valid-user AuthzLDAPLogLevel error </Location> </IfModule> If I understand correctly, mod_authz_ldap will try to search users in the second LDAP if the first server is down or OpenLDAP on it is not running. But in practice, it does not happen. Tested by stopping LDAP on the master, I get the "500 Internal Server Error" when accessing to the Subversion repository. The error_log shows: [11061] auth_ldap authenticate: user quanta authentication failed; URI / [LDAP: ldap_simple_bind_s() failed][Can't contact LDAP server] Did I misunderstand? AuthBasicProvider ldap1 ldap2 only means that if mod_authz_ldap can't find the user in ldap1, it will continue with ldap2. It doesn't include the failover feature (ldap1 must be running and working fine)?

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