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• SQL Server 2008 R2 100% availability

  - by Mark Henderson

  Is there any way to provide 100% uptime on SQL Server 2008 R2? From my experience, the downtimes for the different replication methods are: Log Shipping: Lots (for DR only) Mirroring w. NLB: ~ 45 seconds Clustering: ~ 5-15 seconds And all of these solutions involve all of the connections being dropped from the source, so if the downtime is too long or the app's gateway doesn't support reconnection in the middle of task, then you're out of luck. The only way I can think to get around this is to abstract the clustering a level (by virtualising and then enabling VMWare FT. Yuck. Good luck getting this to work on a quad-socket, 32-core system anyway.). Is there any other way of providing 100% uptime of SQL Server?

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• Setup routing and iptables for new VPN connection to redirect **only** ports 80 and 443

  - by Steve

  I have a new VPN connection (using openvpn) to allow me to route around some ISP restrictions. Whilst it is working fine, it is taking all the traffic over the vpn. This is causing me issues for downloading (my internet connection is a lot faster than the vpn allows), and for remote access. I run an ssh server, and have a daemon running that allows me to schdule downloads via my phone. I have my existing ethernet connection on eth0, and the new VPN connection on tun0. I believe I need to setup the default route to use my existing eth0 connection on the 192.168.0.0/24 network, and set the default gateway to 192.168.0.1 (my knowledge is shaky as I haven't done this for a number of years). If that is correct, then I'm not exactly sure how to do it!. My current routing table is: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface MSS Window irtt 0.0.0.0 10.51.0.169 0.0.0.0 UG 0 0 0 tun0 0 0 0 10.51.0.1 10.51.0.169 255.255.255.255 UGH 0 0 0 tun0 0 0 0 10.51.0.169 0.0.0.0 255.255.255.255 UH 0 0 0 tun0 0 0 0 85.25.147.49 192.168.0.1 255.255.255.255 UGH 0 0 0 eth0 0 0 0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0 0 0 0 192.168.0.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 0 0 0 After fixing the routing, I believe I need to use iptables to configure prerouting or masquerading to force everything for destination port 80 or 443 over tun0. Again, I'm not exactly sure how to do this! Everything I've found on the internet is trying to do something far more complicated, and trying to sort the wood from the trees is proving difficult. Any help would be much appreciated. UPDATE So far, from the various sources, I've cobbled together the following: #!/bin/sh DEV1=eth0 IP1=`ifconfig|perl -nE'/dr:(\S+)/&&say$1'|grep 192.` GW1=192.168.0.1 TABLE1=internet TABLE2=vpn DEV2=tun0 IP2=`ifconfig|perl -nE'/dr:(\S+)/&&say$1'|grep 10.` GW2=`route -n | grep 'UG[ \t]' | awk '{print $2}'` ip route flush table $TABLE1 ip route flush table $TABLE2 ip route show table main | grep -Ev ^default | while read ROUTE ; do ip route add table $TABLE1 $ROUTE ip route add table $TABLE2 $ROUTE done ip route add table $TABLE1 $GW1 dev $DEV1 src $IP1 ip route add table $TABLE2 $GW2 dev $DEV2 src $IP2 ip route add table $TABLE1 default via $GW1 ip route add table $TABLE2 default via $GW2 echo "1" > /proc/sys/net/ipv4/ip_forward echo "1" > /proc/sys/net/ipv4/ip_dynaddr ip rule add from $IP1 lookup $TABLE1 ip rule add from $IP2 lookup $TABLE2 ip rule add fwmark 1 lookup $TABLE1 ip rule add fwmark 2 lookup $TABLE2 iptables -t nat -A POSTROUTING -o $DEV1 -j SNAT --to-source $IP1 iptables -t nat -A POSTROUTING -o $DEV2 -j SNAT --to-source $IP2 iptables -t nat -A PREROUTING -m state --state ESTABLISHED,RELATED -j CONNMARK --restore-mark iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j CONNMARK --restore-mark iptables -t nat -A PREROUTING -i $DEV1 -m state --state NEW -j CONNMARK --set-mark 1 iptables -t nat -A PREROUTING -i $DEV2 -m state --state NEW -j CONNMARK --set-mark 2 iptables -t nat -A PREROUTING -m connmark --mark 1 -j MARK --set-mark 1 iptables -t nat -A PREROUTING -m connmark --mark 2 -j MARK --set-mark 2 iptables -t nat -A PREROUTING -m state --state NEW -m connmark ! --mark 0 -j CONNMARK --save-mark iptables -t mangle -A PREROUTING -i $DEV2 -m state --state NEW -p tcp --dport 80 -j CONNMARK --set-mark 2 iptables -t mangle -A PREROUTING -i $DEV2 -m state --state NEW -p tcp --dport 443 -j CONNMARK --set-mark 2 route del default route add default gw 192.168.0.1 eth0 Now this seems to be working. Except it isn't! Connections to the blocked websites are going through, connections not on ports 80 and 443 are using the non-VPN connection. However port 80 and 443 connections that aren't to the blocked websites are using the non-VPN connection too! As the general goal has been reached, I'm relatively happy, but it would be nice to know why it isn't working exactly right. Any ideas? For reference, I now have 3 routing tables, main, internet, and vpn. The listing of them is as follows... Main: default via 192.168.0.1 dev eth0 10.38.0.1 via 10.38.0.205 dev tun0 10.38.0.205 dev tun0 proto kernel scope link src 10.38.0.206 85.removed via 192.168.0.1 dev eth0 169.254.0.0/16 dev eth0 scope link metric 1000 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.73 metric 1 Internet: default via 192.168.0.1 dev eth0 10.38.0.1 via 10.38.0.205 dev tun0 10.38.0.205 dev tun0 proto kernel scope link src 10.38.0.206 85.removed via 192.168.0.1 dev eth0 169.254.0.0/16 dev eth0 scope link metric 1000 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.73 metric 1 192.168.0.1 dev eth0 scope link src 192.168.0.73 VPN: default via 10.38.0.205 dev tun0 10.38.0.1 via 10.38.0.205 dev tun0 10.38.0.205 dev tun0 proto kernel scope link src 10.38.0.206 85.removed via 192.168.0.1 dev eth0 169.254.0.0/16 dev eth0 scope link metric 1000 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.73 metric 1

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• Perform action based on load avg

  - by sfx

  I'm running some web applications on an debian server and have to struggle with ddos attacks sometimes. It's eating up all my resources and I can't ssh anymore into the server. An idea was to drop all connections if the load avg is too high, so there are still resources for me and accept new connections if the load avg is low enough. Since this has to work under heavy load I'm afraid a cronjob wouldn't be fast enough or take too much resources. tl;dr: Is there a way to configure the behavior if the load avg is above a specific threshold?

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• Software: Launching League of Legends spectator mode from Command Line (Mac)

  - by Alex Popov

  Background: tl;dr at the end League of Legends has a spectator mode, in which you can watch someone else's game (essentially a replay) with a 3 minute delay. Popular LoL website OP.GG has figured out a clever way of hosting these spectator games on their own servers, thereby making them replayable, as opposed to only being available while the game is on (as Riot does it). If you request a replay from OP.GG, it sends a batch file which looks for where the League is situated and then the magic happens: @start "" "League of Legends.exe" "8394" "LoLLauncher.exe" "" "spectator fspectate.op.gg:4081 tjJbtRLQ/HMV7HuAxWV0XsXoRB4OmFBr 1391881421 NA1" This works fine on Windows. I'm trying to get it to work on Mac (which has an official client). First I tried running the same command by hand, (split for convenience) /Applications/ ... /LeagueOfLegends.app/ ... /LeagueofLegends 8393 LoLLauncher \ /Applications/ ... /LolClient spectator fspectate.op.gg:4081 tjJbtRLQ/HMV7HuAxWV0XsXoRB4OmFBr 1391881421 NA1 Running this, however, just starts the LoLLauncher, which closes all the active League processes. The exactly same thing happens if I just call /Applications/ ... /LeagueOfLegends.app/ ... /LeagueofLegends Next I tried seeing what actually happens when Spectator mode is initiated so I ran $ ps -axf | grep -i lol which showed UID PID PPID C STIME TTY TIME CMD 503 3085 1 0 Wed02pm ?? 0:00.00 (LolClient) 503 24607 1 0 9:19am ?? 0:00.98 /Applications/League of Legends.app/Contents/LOL/RADS/system/UserKernel.app/Contents/MacOS/UserKernel updateandrun lol_launcher LoLLauncher.app 503 24610 24607 0 9:19am ?? 1:08.76 /Applications/League of Legends.app/Contents/LoL/RADS/projects/lol_launcher/releases/0.0.0.122/deploy/LoLLauncher.app/Contents/MacOS/LoLLauncher 503 24611 24610 0 9:19am ?? 1:23.02 /Applications/League of Legends.app/Contents/LoL/RADS/projects/lol_air_client/releases/0.0.0.127/deploy/bin/LolClient -runtime .\ -nodebug META-INF\AIR\application.xml .\ -- 8393 503 24927 24610 0 9:44am ?? 0:03.37 /Applications/League of Legends.app/Contents/LoL/RADS/solutions/lol_game_client_sln/releases/0.0.0.117/deploy/LeagueOfLegends.app/Contents/MacOS/LeagueofLegends 8394 LoLLauncher /Applications/League of Legends.app/Contents/LoL/RADS/projects/lol_air_client/releases/0.0.0.127/deploy/bin/LolClient spectator 216.133.234.17:8088 Yn1oMX/n3LpXNebibzUa1i3Z+s2HV0ul 1400781241 NA1 Of Interest: there is (LolClient) which I cannot kill by it's PID. UserKernel updateandrun lol_launcher LoLLauncher.app is launched first. LoLLauncher is launched by the UserKernel (as we can see from the PPID) The very long command (PID: 24927) is how Spectator mode is launched, and is also launched by UserKernel. Spectator mode is launched in exactly the same way that the OP.GG .bat wanted to, with the only difference that Spectator mode connects to Riot instead of OP.GG's spectate server. I tried attaching GDB to the LolClient, but I couldn't get anything meaningful from it since it's an Adobe AIR application (and I've never used GDB with code other than mine own). Next I ran dtruss -a -b 100m -f -p $PID on everything I could think of: the LolClient, the LolLauncher and the UserKernel and skimmed the half a million lines produced. I found stuff like the GET request used to get the information of the game to spectate, but I could not see any launch of the equivalent of League of Legends.exe with spectator options. Finally, I ran lsof | grep -i lol to see if anything else was opened in the process, but didn't find anything that seemed appropriate. Open were UserKernel, LolLauncher, LolClient, Adobe AIR, LeagueofLegends and then Bugsplat, all of which are expected. None of this seemed especially relevant to figuring out how LeagueofLegends was opened into spectator mode. It obviously can be done, since Spectator mode is accessible from within the client. It seems likely that it can be done from the CLI, since Windows can do it and the clients are supposed to equals. Unless I'm missing something in the difference between how UNIX and Windows handle CLI application launches. My question is if there are any other things I can try to figure out how to launch Spectator mode myself. tl;dr: Trying to get into spectator mode from the CLI. It's possible on Windows (see first code block) but it just restarts League on Mac. What else can I try to find what call is made, and how to reproduce it? PS: Please let me know how I can improve this question or its formatting, I'd love to use StackOverflow/SuperUser, but as the guys said on the podcast this week (Ep. 59) it's very intimidating. Sorry for posting this on StackOverflow the first time :(

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• XKB - remap arrow keys and preserve shift behaviour to select text

  - by dgirardi

  I realize arrow key remapping is an old problem, however I cannot seem to find a good solution that lets me select text with SHIFT + remapped keys as I would do with the vanilla arrow keys. For instance, if I remap Caps Lock to ISO_Level3_Shift and set xkb_symbols to read either key <AC08> { [ k, K , Down, Down] }; or key <AC08> { type="THREE_LEVEL", [ k, K , Down ] }; Pressing Shift+CapsLock+K will behave exactly as CapsLock+K (while Shift+Down behaves differently from Down alone). I had somewhat more success using higher level macro utilities and generating keyboard events (i.e. generate both the shift and the arrow keypresses); hoever that approach has a whole set of different problems - often the UI response to a simulated keypress is different from the "real" keypress, and there are performance problems as well - I can type faster than the thing can handle. Tl;dr; how can you shift-select using remapped arrow keys under X?

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• Using TrueCrypt with File Replication on Windows Server

  - by neildeadman

  We have a few folders that are set to replicate to a DR file server off-site. One of these folders contains a file that is a TrueCrypt volume container. When this file is mounted in TrueCrypt, the file won't replicate (fair enough!). I'm looking at alternatives to improve this situation. One solution I currently have is to have a scheduled task to unmount the volume and then every morning as the volume is needed, have someone mount it. This is a pain slightly because the password is known by a few people (I'm not one and neither are my colleagues who would be performing the mounting operation) so we'd need to continually get them to come over and type it in. The other I had was to have one TrueCrypt container on each server and replicate the contents when they are mounted. I wasn't able to get TrueCrypt to see the mounted volume so I guess this is a no go. Any other solutions I have missed or a fix for the above?

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• How do I install and run Tomcat on port 80 as my only web server? (Rooted Ubuntu box)

  - by gav

  Hi All, tl;dr - I have a rooted linux box that I want to run tomcat on as a server (No Apache Web Server) how would you set this up avoiding common security pitfalls? I've written a Grails App that I want to run on a VPS I rent. The VPS has very little memory and I am using it for the sole purpose of running this application so I don't need the apache web server. This is my first venture into Server administration and I'm sure to fall into some well known traps. Should I use iptables to redirect requests from port 80 to 8080? Should I run tomcat as root or as it's own user? What configuration settings would be good for a low memory system expecting less than 10 concurrent users? Hopefully an easy one for you! Anyone who could link to a tutorial would be a personal hero destined for great things no doubt. Gav

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• Bash & 'su' script giving an error "standard in must be a tty".

  - by sHz

  Folks, I'm having an issue with a bash script which runs a particular command as a different user. The background: Running on a Linux box (CentOS), the script is quite simple, its starting the hudson-ci application. declare -r HOME=/home/hudson declare -r RUNAS=hudson declare -r HOME=/home/hudson declare -r LOG=hudson.log declare -r PID=hudson.pid declare -r BINARY=hudson.war su - ${RUNAS} -c "nohup java -jar ${HOME}/${BINARY} >> ${HOME}/${LOG} 2>&1; echo $! > ${HOME}/${PID}" & This is the bridged version of the script, when run, the script exists with "standard in must be a tty". Any ideas on what I could be doing wrong? I've tried Dr Google and all the advise hasn't helped thus far.

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• replace controller, add second controller, or use expander?

  - by longneck

  I have a Proliant DL380 G6 that I am re-purposing as a Hyper-V host for a new, off-site data center that will host our DR services. The server currently has a P410i controller with the 512MB BBWC module. The drives installed are SFF 6G 10K drives. I plan to add the HP 516914-B21 drive cage, which gives me 8 more SFF drives, bringing the total to 16. To get the additional 8 drives connected, I have one of three choices: Install a new controller that can support 16 drives. Install a second controller. Install a SAS expander, such as the HP 468406-B21 recommended by HP's spec sheet for my server. My question is: how do I know if I'm going hit a performance ceiling by putting 16 drives on the P410i or using the expander? And if I am, how do I select an appropriate controller? I'm not sure what specifications I should be looking at.

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• Multi-account Google Apps Calendar Free-busy status?

  - by Andrew Bolster

  I have 3 google apps domain accounts and a personal google account, and until recently, there was little need for the google app's calendars to have any real use; Now however the powers that be finally discovered the smart re-scheduler and the other google tools for managing meetings and schedules; unfortunately I'm now in a position where I've got events notifications all over the place and because each of the calendars do not know about each other, I'm losing all of the advantages of rescheduler / free-busy status. TL;DR, 4 calendars, unified 'free busy' status without having to manually copy every event please.

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• Map specific keys in emacs - Ubuntu

  - by Josh

  On my Mac, I have remapped the capslock key to be another Ctrl, and the key to the right of control to be M (meta?). It was real easy, the capslock was in sys prefs, and the M key was a pref in terminal. I cannot figure out how to do it on my Ubuntu 10.10 computer though. There was no remap capslock that I could find under any of the three keyboard pref menu items, and there are no prefs under the terminal that I can find. Can someone advise? I want the windows key on the keyboard to be M, if that matters. tl;dr; Ubuntu 10.10: Map capslock as Ctrl and Windows key as Meta (emacs) Thanks! EDIT: Found Capslock under System - Prefs - Keyboard - Layouts - USA - Options - Ctrl Key Position - Make CapsLock an additional Ctrl

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• win 2008 core create a partition with an offset to allow other partition expand

  - by Rqomey

  We are running a win 2008 core host in a HyperV role. We have expanded the logical drive on a RAID 1+0 array belonging to the server, as we needed more space. We have two data partitions D: and E: I want to expand them both so they use all space, and are equally sized. There is data on all partitions, although E is not in live use (so files can be moved and copied from it. Current: What I want- temporary Partition (F:) at end of drive: I am going to create a temporary partition F: so I can move the files from E: onto it, then delete E:, expand D: to the desired size, then rename F: to E: To do this I need to create F: from the end of the drive, ie. have unused space between E: and F: tl;dr How do I create a partition with a large offset in Windows server?

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• wget recursively with -np option still ascends to parent directory

  - by vectra

  tl;dr: will `wget --no-parrent -r ' download from a directory above the given url's directory? when using wget to download, say images, recursively from example.com/a/b with the -r and -np options, will a picture that is under example.com/a/c/ be downloaded when example.com/a/b/ delivers a html-file containing a link to the picture? if so, how do i get all pictures, that are in a folder and it's subfolders and only those? the description of the option --no-parent says "Do not ever ascend to the parent directory when retrieving recursively". anyway directory browsing delivers a link to the parent directory, which wget will follow, despite mentioned option. now what did i miss? edit: using GNU Wget 1.12

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• Filemaker Server Not Installing and Windows Problems

  - by Shelly

  When I tried installing Filemaker Server 8.0 on Windows 2003 Server Standard Edition R2, an error message pop up that states: MMC has detected an error in a snap-in. It is recommended that you shut down and restart MMC. After this message pops up, Filemaker Server freezes. I'm also having problems with openssl and running executable files, but am not sure if the 2 are related. Error message for openssl states: Openssl.exe encountered a problem and needed to close. In one of the computers connected to the network running this same Server 2003 R2, when I tried double-clicking on Dr. Web antivirus to do a scan, nothing happens. I have done this many times before reinstalling the server, and it never gave trouble before this. Any help given is appreciated.

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• Sudden slow read & write speed on all IO

  - by user23392

  I have a custom built rig that has 2 storage drives. for OS: Western Digital 1.0TB HARD DR 64MB for other stuff: Corsair Performance 3 128GB (SSD) [ expected read speed: 400 mb/s ] The system was incredibly fast for a couple of months, then one day i was playing a game then it started to get buggy (some sounds and objects disappearing), i stopped the game and the system seemed to be unstable so i had to shut it down, next morning i couldn't start it up, it was saying something about corrupt device. I formatted both disks and installed a fresh copy of windows, all i can say that since that day the system was never like before, it takes 10 minutes to boot up (the icons and desktop slowly appear). but once it's done the slowness isn't as noticeable. Here's my benchmark on the HDD ( read speed - write speed ): And the SSD: Anyone knows what could be the issue?

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• Network Share unavailable after DNS Change

  - by Justin Largey

  Hi, I have a server, called Server1 with various network shares on it. Our users map to this share using \\Server1\FileShareName1. During a DR Test, we rerouted all network traffic from Server1 to Server21. All folder shares are set up on Server21. We were hoping the the network shares would still be accessible using \\Server1\FileNameShare1, unfortunately, they are not. Does anyone know why this is happening? This is a Win2003 Environment, and DNS was flushed. I confirmed that IP addresses are matching between the two servers. Any help or insight is much appreciated.

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• How can I make Chrome work more like Firefox?

  - by rhooligan

  After Firefox broke my add-ons yet again, I decided to give Chrome a second look. To my surprise all the add-ons are available. What I am missing though is the drop-down search bar. First, I've disabled the search from the location bar. Now I want to add a combo box that is always visible where I can select the engine to do searching. I downloaded a search extension (Search Box), but it's an icon that needs to be clicked before you can interact with it: TL;DR; I want a box that is always visible and can change the search engine from a drop-down. Is there an extension like this available in Chrome?

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• How can I tell what command is running on the remote end of an ssh connection?

  - by user268385

  Tl;dr - how do I find the name of the command (eg $BASH_COMMAND) running on the remote end of an ssh connection? ... My example setup is two tmux vertical panes, LH pane runs a local vim session with vertical split, RH pane runs an ssh session running vim, again with a vertical split. Using tmux-navigator I can navigate from left to right over the first 3 vim buffers, but the 4th (far right hand one) is inaccessible. The reason for this is that tmux-navigator tests the value of 'pane_current_command' and compares it to 'vim' before deciding which keystrokes to dispatch. On the right hand tmux pane, the current command is 'ssh' and not 'vim'. What I want to do is test for (pane_current_command =~ 'ssh'), and if so, examine the command that is running on the far side of the connection? I cannot find a way to get hold of this, so any suggestions would be welcome? For information, the problem is almost the same as this one, but without the nested tmux sessions: https://github.com/christoomey/vim-tmux-navigator/issues/12

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• Tomcat directly serve static (css, js) files shared by multiple applications

  - by Josvic Zammit

  I'm using the ExtJS framework which has a bulk of js and css files that are used for all apps. I intend to share these between a number of web applications (different war files). For this reason I would like to serve ExtJS js and css directly from the web server, in my case Tomcat6, which can be used to serve static files, as in this helpful link. Therefore I put my files under /var/lib/tomcat6/webapps/ROOT/extjs/. The static files that are directly under that directory are served correctly, e.g. /extjs/ext.js correctly serves the file at /var/lib/tomcat6/webapps/ROOT/extjs/ext.js. However files in lower-level directories, for example /extjs/welcome/css/welcome.css, which should serve the file at /var/lib/tomcat6/webapps/ROOT/extjs/welcome/css/welcome.css, return a 404. TL/DR Tomcat serves static files only at top-level directory. A 404 is returned for files deeper in the hierarchy. Config file contents: server.xml application's web.xml

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• permissions destroyed

  - by n00b32

  yes yes i know im stupid but while i was veeeery late i tried to fix one thing asap and ended up doing chmod 777 -R /* it chmoded dr-xr-xr-x 2 root root 4096 2011-02-15 13:12 bin drwx------ 3 root root 4096 2010-09-07 15:57 boot d-wx-wx-wx 15 root root 13680 2010-12-11 05:48 dev drwx------ 3 root root 4096 2010-09-09 05:24 emul d-wx-wx-wx 110 root root 4096 2011-03-07 07:12 etc drwx------ 2 root root 4096 2010-09-10 04:35 firewall because of spelling mistake... can some send me a tree of permissions for those on debian so ill have a lot less work ? is there another way i can fix them ?

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• NFS default to 777

  - by ipengineer

  I have an NFS share. This share is shared between several different applications. Our web server is running PHP and when it creates directories it is not setting the permissions correctly so it cannot write to the directory once created. How can I mount this NFS share to where PHP has full read/write access? Below is the directory that has been created along with the media server export options and the mount options on the web server. Ideally I could set the permissions on /opt/mount and whatever group/user is on that directory when I mount to that point the share assumes those permissions. dr----x--t. 2 nobody nobody 4096 Jun 5 2014 user_2 Mount output: media.dc1:/home/fs_share on /opt/mount type nfs (rw,vers=4,addr=10.10.20.127,clientaddr=10.10.20.42) Exports file from media server: /home/fs_share 10.10.20.0/255.255.255.0(rw,sync,no_root_squash)

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• How to overcome shortcomings in reporting from EAV database?

  - by David Archer

  The major shortcomings with Entity-Attribute-Value database designs in SQL all seem to be related to being able to query and report on the data efficiently and quickly. Most of the information I read on the subject warn against implementing EAV due to these problems and the commonality of querying/reporting for almost all applications. I am currently designing a system where almost all the fields necessary for data storage are not known at design/compile time and are defined by the end-user of the system. EAV seems like a good fit for this requirement but due to the problems I've read about, I am hesitant in implementing it as there are also some pretty heavy reporting requirements for this system as well. I think I've come up with a way around this but would like to pose the question to the SO community. Given that typical normalized database (OLTP) still isn't always the best option for running reports, a good practice seems to be having a "reporting" database (OLAP) where the data from the normalized database is copied to, indexed extensively, and possibly denormalized for easier querying. Could the same idea be used to work around the shortcomings of an EAV design? The main downside I see are the increased complexity of transferring the data from the EAV database to reporting as you may end up having to alter the tables in the reporting database as new fields are defined in the EAV database. But that is hardly impossible and seems to be an acceptable tradeoff for the increased flexibility given by the EAV design. This downside also exists if I use a non-SQL data store (i.e. CouchDB or similar) for the main data storage since all the standard reporting tools are expecting a SQL backend to query against. Do the issues with EAV systems mostly go away if you have a seperate reporting database for querying? EDIT: Thanks for the comments so far. One of the important things about the system I'm working on it that I'm really only talking about using EAV for one of the entities, not everything in the system. The whole gist of the system is to be able to pull data from multiple disparate sources that are not known ahead of time and crunch the data to come up with some "best known" data about a particular entity. So every "field" I'm dealing with is multi-valued and I'm also required to track history for each. The normalized design for this ends up being 1 table per field which makes querying it kind of painful anyway. Here are the table schemas and sample data I'm looking at (obviously changed from what I'm working on but I think it illustrates the point well): EAV Tables Person ------------------- - Id - Name - ------------------- - 123 - Joe Smith - ------------------- Person_Value ------------------------------------------------------------------- - PersonId - Source - Field - Value - EffectiveDate - ------------------------------------------------------------------- - 123 - CIA - HomeAddress - 123 Cherry Ln - 2010-03-26 - - 123 - DMV - HomeAddress - 561 Stoney Rd - 2010-02-15 - - 123 - FBI - HomeAddress - 676 Lancas Dr - 2010-03-01 - ------------------------------------------------------------------- Reporting Table Person_Denormalized ---------------------------------------------------------------------------------------- - Id - Name - HomeAddress - HomeAddress_Confidence - HomeAddress_EffectiveDate - ---------------------------------------------------------------------------------------- - 123 - Joe Smith - 123 Cherry Ln - 0.713 - 2010-03-26 - ---------------------------------------------------------------------------------------- Normalized Design Person ------------------- - Id - Name - ------------------- - 123 - Joe Smith - ------------------- Person_HomeAddress ------------------------------------------------------ - PersonId - Source - Value - Effective Date - ------------------------------------------------------ - 123 - CIA - 123 Cherry Ln - 2010-03-26 - - 123 - DMV - 561 Stoney Rd - 2010-02-15 - - 123 - FBI - 676 Lancas Dr - 2010-03-01 - ------------------------------------------------------ The "Confidence" field here is generated using logic that cannot be expressed easily (if at all) using SQL so my most common operation besides inserting new values will be pulling ALL data about a person for all fields so I can generate the record for the reporting table. This is actually easier in the EAV model as I can do a single query. In the normalized design, I end up having to do 1 query per field to avoid a massive cartesian product from joining them all together.

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• Learn Lean Software Development and Kanban Systems

  - by Ben Griswold

  I did an in-house presentation on Lean Software Development (LSD) and Kanban Systems this week.  Beyond what I had previously learned from various podcasts, I knew little about either topic prior to compiling my slide deck.  In the process of building my presentation, I learned a ton.  I found the concepts weren’t very difficult to grok; however, I found little detailed information was available online. Hence this post which is merely a list of valuable resources. Principles of Lean Thinking, Mary Poppendieck Lean Software Development, May Poppendieck Lean Programming, Mary Poppendieck Lean Software Development, Wikipedia Implementing Lean Software Thinking: From Concept to Cash, Poppendieck Lean Software Development Overview, Darrell Norton Lean Thinking: Banish Waste and Create Wealth in Your Corporation The Goal: A Process of Ongoing Improvement The Toyota Way Extreme Toyota: Radical Contradictions That Drive Success at the World’s Best Manufacturer Elegant Code Cast 17 – David Laribee on Lean / Kanban Herding Code Episode 42: Scott Bellware on BDD and Lean Development Seven Principles of Lean Software Development, Przemys?aw Bielicki Kanban Boards for Agile Project Management with Zen Author Nate Kohari Herding Code 55: Nate Kohari brings Your Moment of Zen James Shore on Kanban Systems Agile Zen Product Site A Leaner Form of Agile, David Laribee Kanban as Alternative Agile Implementation, Mark Levison Lean Software Development, Dr. Christoph Steindl Glossary of Lean Manufacturing Terms Why Pull? Why Kanban?, Corey Ladas

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• Show Notes: Bob Hensle on IT Strategies from Oracle

  - by Bob Rhubart

  The latest ArchBeat Podcast (RSS) features a conversation with Oracle Enterprise Architecture director Bob Hensle (LinkedIn). Bob talks about IT Strategies from Oracle, an extensive library of reference architectures, best practices, and other documents now available (it’s a freebie!) to registered Oracle Technology Network members. Listen to Part 1 Bob offers some background on the IT Strategies from Oracle project and an overview of the included documents. Listen to Part 2 (Feb 16) A discussion of how SOA and other issues are reflected in the IT Strategies documents. Share your feedback on any of the documents in the IT Strategies from Oracle Library: [email protected] For a nice complement to the IT Strategies from Oracle Library, check out Oracle Experiences in Enterprise Architecture, an ongoing series of short essays from members of the Oracle Enterprise Architecture team based on their field experience. In the Pipeline ArchBeat programs in the works include an interview with Dr. Frank Munz, the author of Middleware and Cloud Computing, excerpts from another architect virtual meet-up, and a conversation with Oracle ACE Director Debra Lilley about her insight into Fusion Applications. . Stayed tuned: RSS Technorati Tags: oracle,oracle technology network,software architecture,enterprise architecture,reference architecture del.icio.us Tags: oracle,oracle technology network,software architecture,enterprise architecture,reference architecture

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• ArchBeat Top 20 for March 11-17, 2012

  - by Bob Rhubart

  The 20 most-clicked links as shared via my social networks for the week of March 11-17, 2012. Start Small, Grow Fast: SOA Best Practices article by @biemond, @rluttikhuizen, @demed Packt Publishing offers discounts of up to 30% on 60+ Oracle titles IT Strategies from Oracle; Three Recipes for Oracle Service Bus 11g ; Stir Up Some SOA Oracle Cloud Conference: dates and locations worldwide Applications Architecture | Roy Hunter and Brian Rasmussen How Strategic is IT? - Assessing Strategic Value | Al Kiessel White Paper: An Architect’s Guide to Big Data | Dr. Helen Sun, Peter Heller Getting Started with Oracle Unbreakable Enterprise Kernel Release 2 | Lenz Grimmer Great Solaris 10 features paving the way to Solaris 11 | Karoly Vegh Who the Linux Developer Met on His Way to St. Ives | Rick Ramsey Peripheral Responsibilities Required for Large IDM Build Outs (Including Fusion Apps) | Brian Eidelman IOUG Real World Performance Tour, w/Tom Kyte, Andrew Holdsworth, Graham Wood Configure IPoIB on Solaris 10 branded zone | Leo Yuen Oracle OpenWorld 2012 Call for Papers Use Case Assumptions versus Pre-Conditions | Dave Burke Handling Custom XML documents in Oracle B2B | @Biemond Building a Coherence Cluster with Multiple Application Servers | Rene van Wijk XMLA vs BAPI | Sunil S. Ranka The Java EE 6 Example - Running Galleria on WebLogic 12 - Part 3 | @MyFear Public Sector Architecture | @jeremy_forman, @hamzajahangir Thought for the Day "The goal of Computer Science is to build something that will last at least until we've finished building it." —Anonymous

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