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  • SSH tunnel for socks5 proxy is slow with concurrent load

    - by RawwrBag
    I ssh to a remote AWS server using Ubuntu. I use ssh's port forwarding capabilities to do this. I have tried forwarding a dynamic port (ssh -D) or a single port (ssh -L with dante running as a remote socks server). Both are equally slow. I also tried different ciphers (ssh -c). Concurrent TCP connections pretty much do not work. For example, I can go to speedtest.net and start a test (which is fairly fast, probably maxes out my line speed) and if I try and do anything (i.e. load google.com) while the test is still running, all the additional connections seem to hang until the speed test is over. I realize OpenSSH is single-threaded. Is this the problem? It doesn't even show up on my top. Same goes for sshd on the remote server -- no processor hit. Is there anyway to bump ssh performance or should I step up to OpenVPN or something better suited for this?

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  • Intel Ethernet Bottlenecking Internet?

    - by Donald Darma
    I'm having trouble with my internet speeds. So I just recent build a pc and everything is fine. I installed the Intel drivers and connected to the internet. It connects but I'm only half the speed I should be getting. My normal speed is 20mbps but speedtest.net is only showing 10. It can't be my ISP (which is TWC if anyone is asking) because my other devices like my laptop and my smartphone are showing 20 down. Heres my system: CPU: i5 4430 HSF: Stock cooler Mobo: Gigabyte Z87MX-D3H GPU: x2 MSI R7950-3GD5/OC BE RAM: Crucial Ballistix Tactical Tracer 8GB dual channel PSU: Silencer High Performance Power Supply 750 Watt 80+ (It's a subdivision of OCZ) HDD: Seagate Barracuda 7200RPM 3TB SSD: Samsung 840 Evo 120 GB Case: Corsair Obsidian 350D Edit: I am using the stock adapter that is on the motherboard. I know for a fact that the cable is good because I used it on my laptop and it ran fine. Its a CAT5E cable. I also ran IPERF and its giving me the same results, 10 mbps.

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  • VCL - configuration for Magento and Varnish 3.0.2

    - by Tomas
    I would like to kindly ask if there's someone who can help me configure Varnish for Magento to reach far more hits. My current ratio from varnishstat is: cache_hit=271 cache_miss=926 I'm kindly asking this because I've googled almost every site related to this theme, but 99.9% of configurations don't work because of outdated code. Details of my set-up: I use Varnish on port 80, Apache on port 81, PageCache as Magento varnish module, APC for PHP speed and Memcached for dynamic caching. Load speed is about 1.5s on home-page (Pingdom.com average results) USA ping & 2.5s Europe. Servers are located in Toronto, Canada. EDIT: This is my full VCL configuration http://pastebin.com/885BzHCs (I just use xxx.xxx.xxx.xxx for my IPs) This is the info from the command (varnishtop -i TxHeader -I Cookie): TxHeader Cookie: frontend=965b5...(*lots of numbers); adminhtml=3ae65...(*lots of numbers); EXTERNAL_NO_CACHE=1 "(*lots of numbers)" is just my adding to the info Any idea how to avoid Varnish hitting this cookies? (If I got correctly the idea about avoiding Vanrish hitting the cookie and not caching the home page). Thank you for any help!

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  • Gigabit LAN not working on ASUS M2N-MX

    - by chmod
    Today I replace my FastEthernet switch with a newly bought gigabit switch (DGS-1008A). All computers in my house are displaying that the connection speed is 1 Gbps except for one. The computer that is not working is an ASUS M2N-MX which contain an onboard gigabit NIC. See ASUS link for confirmation http://www.asus.com/Motherboards/AMD_AM2/M2NMX/ Here are some info of the machine OS: Windows 7 Ultimate SP1 64bit BIOS version: 1004 (latest) Driver: installed via Windows update (latest from Windows update) Windows Update: fully updated The machine is reformatted 3 days ago, so it's pretty clean, no junk, no virus, etc Cable: Amp CAT5E 5 meters In device manager, the name of the NIC is "NVIDIA nForce 10/100/1000 Mbps Ethernet" What I have try: I did try to install the driver provided in ASUS website, but there isn't any for Windows 7 64 or Vista 64. I did try to install the latest nForce340/6100, downloaded from Nvidia website. However, the LAN driver refuse to install, it complain that I already have the best driver installed. I looking in the property -- advance tab -- Speed/duplex settings, in an attempt to force it to run at 1000Mbps, but there is no 1000Mbps choice, only 10 and 100Mpbs. I change the CAT5E cable (use one from another computer that is running gigabit without problem) Anyone have this issue or know how to solve it? Thanks

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  • How do I repartition an SDHC card in Windows?

    - by Peter Mortensen
    How do I repartition an SDHC card (4 GB or more)? Do I need third-part tools or Linux (a live CD solution would be OK)? In Windows' Disk Management the option Delete Partition is dimmed out: I can reformat the card as FAT32, copy files to and from the card and even change the file system to NTFS using the command line command CONVERT, but not repartition it. The article How to Partition an SD Card in Windows XP talks about using "a Windows enabler program" which sound rather dubious to me. I have tried to change from “Optimize for quick removal” to “Optimize for performance”. The option to format as NTFS appeared, but the Delete Partition option is still dimmed out. Platform: Windows XP 64-bit SD card reader: USB 2.0 device, LogiLink® CR0005C Cardreader 3,5' USB 2.0 intern 54-in-1 mit USB Front Kingston 16 GB SDHC card, speed class 4. (It could be formatted as FAT32 and successfully used in a 4 GB ReadyBoost setup (Windows 7).) I have also tried on different versions of Windows and with different cards with the same result: Kingston 4 GB SDHC card, speed class 4 (the one shown in the screenshot) Transcend 2 GB (not marked as SDHC, but SD) Windows 7 32-bit (albeit with a somewhat an older card reader) and Windows XP 32-bit on an EliteBook 8730w

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  • Capabilities of business and SOHO routers

    - by Q8Y
    I'm currently studying for the CCNA certifications (especially for Cisco routers and configuration). I know that business routers provide more features than SOHO routers, the processing speed and RAM can be enough. Assume I need to connect a number of users through a network (accessing internet, share files, printers, ...). I have a high speed connection to the internet and I already applied QoS. How can I find out how many users such a single (SOHO) router could handle? In my case I'd attach to it multiple switches until I have the number of ports needed. Would everything work well and smoothly with 50 users? What about 300? At which point would I need a business router instead? If I implemented VLAN here, would it make any difference in the performance? When do I really need to use more than one router? (Both SOHO and business) I'm thinking that I may need them only if I want to increase the performance (instead of replacing the existing one) and if I have multiple locations, so in this situation I need to have multiple routers, right? Put differently: Is there is a need to have another router if my business all in one place?

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  • How can I confirm that burn process was completed successfully??

    - by infant programmer
    Just now I tried to make a duplicate copy of my Windows XP Pro SP3 CD. I had set 32X speed while the max speed allowed is 48X. And checked "Verify the Data after burning". I didn't observe how much % did it complete. But after 15 mins (which is sufficient period to burn disc), I heard "Fatal Error" sound. When I saw the monitor, There was a message box which was showing "Error while burning Disc", I saved the error log which you can find here click_me. How do I acknowledge that burning process is done?? Well. my PC is able to read the CD and CD is bootable too.. I am not sure .. whether the burning process got failed or the verify Process! Please let me know if you have come across or aware of such situation .. As it is XP installation CD .. I don't want to do trial and error method. regards,

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  • How can I confirm that burn process is completed successfully??

    - by infant programmer
    Just now I tried to make a duplicate copy of my Windows XP Pro SP3 CD. I had set 32X speed while the max speed allowed is 48X. And checked "Verify the Data after burning". I didn't observe how much % did it complete. But after 15 mins (which is sufficient period to burn disc), I heard "Fatal Error" sound. When I saw the monitor, There was a message box which was showing "Error while burning Disc", I saved the error log which you can find here click_me. How do I acknowledge that burning process is done?? Well. I my PC is able to read the cd and it is bootable too.. I am not sure .. whether the burning process got failed or the verify Process! Please let me know if you have come across or aware of such situation .. As it is XP installation CD .. I don't want to do trial and error method. regards,

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  • WD Caviar Green Extremely Slow

    - by Steven
    I am encountering a really weird problem on my WD Caviar Green HDD. Well first of all I have 2 HDDs on my Desktop, one 160GB Seagate holding my Win7 Ultimate x64 and the problematic one, WD 1.5 Caviar Green for storage purpose. My problem is kinda weird, when I transfer files from my Seagate(C:) to my WD (D:) the speed is good (50-60MB/s). Then the problem arises when I transfer too "many" large files, the transfer speed would go straight down to kilobytes/s. Well after I cancelled the transfer and access my D:, even entering a folder requires loading for like 10 seconds. Such problem not only arises when I am transferring files to my D:, it seems like my WD can't handle much activities. For instance, last time I installed my game on D: and I would face much lag after playing for some time. When the same game is installed on C: no problem arises. Does anyone knows what is the problem? P/S: There was one temporary solution that I used to tried. After the "situation" occurs, I tried to access as many folders on D: as I can and let it load, repeating such actions and giving it some time bring the D: back to speedy transfer. However, large transfers would causes the situation to happen again. Does it have something to do with cache whatsoever?

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  • nVidia performance with newer X and newer driver abysmal with Compiz

    - by Nakedible
    I recently upgraded Debian to Xorg 2.9.4 and installed nvidia-glx from experimental, version 260.19.21. This was somewhat of an uphill battle as the dependencies for the experimental nvidia-glx package are still somewhat broken. I got it to work without forcing the installation of any packages and without modifying the packages. However, after the upgrade compiz performance has been abysmal. I am using the desktop wall plugin and switching viewports is really slow - takes a few seconds for each switch. In addition to this, every effect that compiz does, such as zoom animations for icons when launching applications, takes seconds. The viewport switching speed changes relative to the amount of windows on that virtual screen - empty screens switch almost at normal speed, single browser windows work almost decently, but just 4 rxvt terminals slows the switches down to a crawl. My compiz configuration should be pretty basic. Xorg is likewise configured without anything special - the only "custom" configuration is forcing the driver name to be "nvidia". I've fiddled around with the nvidia-settings and compizconfig trying different VSync settings, but none of those helped. My graphics card is: NVIDIA GPU NVS 3100M (GT218) at PCI:1:0:0 (GPU-0). This is laptop GPU that is from the Geforce GTX 200 series. Graphics card performance should naturally be no problem. EDIT: In the end, nothing really worked, and I got really annoyed with the state of compiz and its support in Debian. Many nVidia driver revisions have passed and I am using Gnome 3 now, so I am accepting the best answers to this question even though the issue was not resolved.

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  • Is my "Generic" USB Flash Drive broken?

    - by Jesse J.
    So here is the situation. I find myself technological knowledgeable about many things ( I love to code, whether it's websites, C#, C++ or so on). However: My 2 toddlers (my wife actually) bought me a "Generic" 128 GB USB Storage Device (Usb Flash Drive) for Father's Day. I thought awesome at first..... WRONG! Nothing but problems with it. 3-4mb/s MAX transfer speed. I can bear with it. BUT! When I went to reformat my computer I transferred my save files from my games over to the stick and then the USB Stick managed to become corrupted. Not just a simple format would work either. It's screwed. I tried to use (Manually changed usb drive letter troubleshooting it to X) "chmod X: /X /F /R" with administrator rights, I did this after a long session to make it work with no errors (had to delete the log) and I finally recovered the files, however when I go to use it (transfer to or from) it transfers a couple kb to the stick or from it and then freezes, It says (Windows 7): Name: From: Folder (X:\File\Location) To: Folder C:\Users\Username\Desktop) Items Remaining: 0 (0 bytes) Speed: 0 bytes/second It does this forever... and ever... and ever... It transfered 3 files atleast, and then stopped. This is a new USB Stick bought from a "High" reputation company on eBay. Is the USB Stick screwed?

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  • Connect USB hard drive to wireless router on RJ45 port? Possible?

    - by lawphotog
    just a quick story behind. I was trying to set up wireless networked hard drive at home. My wireless router doesn't take USB. I am considering few options. First i was considering to get something like WD My Cloud. My router is an old one provided by service provider. It only has 10/100 Ethernet. WD My Cloud has Gigabit interface. So unless i changed a new router, data transfer will be slow. So upgrading the router is a must if i want fast transfer speed. Plus I already own an external hard drive with USB 3.0 interface. So if I get a router like Netgear D6300, i can get a decent speed wireless shared drive at home. And i can use my existing HDD instead of WD My Cloud. But the router isn't cheap so I am saving up for that. In the meantime I found out the existence of USB to RJ45 adaptor. I read the reviews and some say it works for them and for some don't. They didn't really say what they were trying to do so I'm confused. So if i bought an adaptor like this, can i connect my existing HDD (USB) with my existing router (RJ45) and use it as a shared drive for data transfer? I know it will be slow as the adaptor will only have USB 2.0 and 10/100 for Ethernet. But it's fine as it's for temporary until i got my new router.

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  • disable specific PCI device at boot

    - by Rhymoid
    I've just reinstalled Debian on my Sony VAIO laptop, and my dmesg and virtual consoles all get spammed with the same messages over and over again. [ 59.662381] hub 1-1:1.0: unable to enumerate USB device on port 2 [ 59.901732] usb 1-1.2: new high-speed USB device number 91 using ehci_hcd [ 59.917940] hub 1-1:1.0: unable to enumerate USB device on port 2 [ 60.157256] usb 1-1.2: new high-speed USB device number 92 using ehci_hcd I believe these messages are coming from an internally connected USB device, most likely the webcam (since that's the only thing that doesn't work). The only way I can seem to have it shut up (without killing my actually useful USB ports) is to disable one of the USB host controllers: # echo "0000:00:1a.0" > /sys/bus/pci/drivers/ehci_hcd/unbind This also takes down my Bluetooth interface, but I'm fine with that. I would like this setting to persist, so that I can painlessly use my virtual console again in case I need it. I want my operating system (Debian amd64) to never wake it up, but I don't know how to do this. I've tried to blacklist the module alias for the PCI device, but it seems to be ignored: $ cat /sys/bus/pci/devices/0000\:00\:1a.0/modalias pci:v00008086d00003B3Csv0000104Dsd00009071bc0Csc03i20 $ cat /etc/modprobe.d/blacklist blacklist pci:v00008086d00003B3Csv0000104Dsd00009071bc0Csc03i20 How do I ensure that this specific PCI device is never automatically activated, without disabling its driver altogether? -edit- The module was renamed recently, now the following works from userland: echo "0000:00:1a.0" > /sys/bus/pci/drivers/ehci-pci/unbind Still, I'm looking for a way to stop the kernel from binding that device in the first place.

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  • What method of MySQL mirroring should I use for this?

    - by user45745
    I'm running an web application hosting service (basically hosting forums for free), and I have two remote servers at my disposal. The code for the application is stored on both servers and isn't a problem, but I'm wondering how to deal with the databases. When someone goes onto a site *.example-host.com, they are sent to one of the two servers and both must be capable of loading the forums from a database. The database must also have write access, for when new members register or post topics etc. The main requirement is speed, but uptime is also important (if a server goes out, the site should still work). I have a few options, but I'm inexperienced and not sure which to go with: 1) [PHP] Split the forum records 50:50 between the two servers. If a server does not have the record for a forum requested, it can request it from the other by remote MySQL and load it. This idea sounded okay, until I realised that 50% of the time, users would be waiting significantly longer for pages to load. I also realised that if one of the servers went down, half the forums would be inaccessible and registrations would have to be disabled. 2) [MySQL] Dual master replication. This would attempt to mirror the two databases and sounds perfect, but I've heard that it can be very problematic. I don't know how fast this is. 3) [MySQL] Use a standard replication, distribute read only queries on both nodes and read/write queries to the master. This sounds like a good option, but again, I'm not sure on speed. I also don't know what would happen if the master server went down. If you have any other suggestions, please post them :)

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  • FDE / SSD - partition and leave some unencrypted?

    - by Web Design Hero
    Just bought a used beast of a desktop pc. The system drive is setup as a Raid 0 SSD (Intel 510 SSD Drives) with 128 each. I will probably not have to many programs beyond office and maybe Adobe CS if I spring for it, I will be keeping big data on a regular hdd. My question is about setting up TrueCrypt with my configuration. I have not previously done full disk encryption, but I feel that its probably a good idea. I have done some speed tests using file containers on the hdd and the sdd with truecrypt. While there is a huge hit with the SSDs and Truecrypt, it still outperforms the hdd on its own by a good margin, so I think i will be okay for my needs with truecrypt. I have seen in a few places that they recommend partitioning the drive and leavign some of the SSD not inside truecrypt, does this really make a difference? If so, how much should I leave? Will there be any issue in the Raid0 configuration? I am not really concerned about all the wear leveling issue, rather loose data and be secure, but since I don't need all that space neccesarily, I would like to optimize my setup for security and speed.

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  • Mysql InnoDB and quickly applying large updates

    - by Tim
    Basically my problem is that I have a large table of about 17,000,000 products that I need to apply a bunch of updates to really quickly. The table has 30 columns with the id set as int(10) AUTO_INCREMENT. I have another table which all of the updates for this table are stored in, these updates have to be pre-calculated as they take a couple of days to calculate. This table is in the format of [ product_id int(10), update_value int(10) ]. The strategy I'm taking to issue these 17 million updates quickly is to load all of these updates into memory in a ruby script and group them in a hash of arrays so that each update_value is a key and each array is a list of sorted product_id's. { 150: => [1,2,3,4,5,6], 160: => [7,8,9,10] } Updates are then issued in the format of UPDATE product SET update_value = 150 WHERE product_id IN (1,2,3,4,5,6); UPDATE product SET update_value = 160 WHERE product_id IN (7,8,9,10); I'm pretty sure I'm doing this correctly in the sense that issuing the updates on sorted batches of product_id's should be the optimal way to do it with mysql / innodb. I'm hitting a weird issue though where when I was testing with updating ~13 million records, this only took around 45 minutes. Now I'm testing with more data, ~17 million records and the updates are taking closer to 120 minutes. I would have expected some sort of speed decrease here but not to the degree that I'm seeing. Any advice on how I can speed this up or what could be slowing me down with this larger record set? As far as server specs go they're pretty good, heaps of memory / cpu, the whole DB should fit into memory with plenty of room to grow.

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  • Very high Magento/Apache memory usage even without visitors (are we fooled by our hosting company?)

    - by MrDobalina
    I am no server guy and we have issues with our speed so I come here asking for advise. We have a VPS with 2 cores and 2gb of RAM at a Magento specialized hosting company. Over the course of the last weeks our site speed has gotten worse, even though our store is new, has less than 1000 SKUs and not even 100 visitos a day. At magespeedtest.com we only get 1.87 trans/sec @ 2.11 secs each with a mere 5 concurrent users. Our magento log files are clean, we have no huge database tables or anything like that. When we take a look at our server real time stats, we see that the memory usage jumped up from about 34% to 71% and now 82% in just a few days in idle, with no visitors on the site. Our hosting company said that we do not need to worry about that as it`s maybe related to mysql which creates buffers (which are maybe not even actually being used) and what is important is CPU and swap - stats are ok here. They also said that the low benchmark scores are caused by bad extensions or template modifications on our side. We are not sure if we can trust that statement as we only have 4 plugins installed (all from aheadworks and amasty which are known to be one of the best magento extension developers). Our template modifications are purely html and css, no modifications to the php code. Our pagespeed is ranked with 93/100 in firebug and Magento is properly configured, so the problem really just gets obvious when there are a handful of users on the site at the same time. Can anyone confirm our hosting`s statement about memory usage and where can I start looking for a solution?

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  • Burning Linux ISO to DVD and making it bootable.

    - by toc777
    Hi everyone, I just downloaded the Fedora 14 Live-Desktop ISO and used CDBurnerXP to burn the image to a DVD. For some reason the first time I burned the image nothing showed up on the DVD when I accessed it even though CDBurnerXP said it had successfully burned to the disk. I did it again and the ISO shows up on the disk (I don't think this is right, should it be the files inside the image that show up on disk or the image file??). The problem now is my dell PC can't find the ISO when I try to boot from it. I get an error saying it can't boot from the CD. I have verified the ISO image as directed from the Fedora website. My question is how do I make a bootable CD from a Fedora Live-Desktop ISO? How can I verify that the ISO was written to the CD correctly and has anyone had any issues booting from a CD using a Dell desktop (I'm not at home at the moment so I can't check what model it is but its old enough, I've had it for about 5 years). EDIT: All that needed to be done was to burn the image to CD as an image and not a data file. The first three times failed, I'm not sure if this was because of faulty DVD's or if the write speed was too high (16x). I put in a new DVD and changed the write speed to 8x, the image was then properly burned to the disk without any errors. Thanks.

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  • Display on secondary video card (Nvidia 8400 GS): horrible refresh, bogs system

    - by minameismud
    This is my work computer, but it's a small shop. We do business software development. The most hardcore thing we create is some web animations with html5 and fancy javascript/css. The base machine is a Dell Precision T3500 - Xeon W3550 (3.07GHz quad), 6GB ram, pair of 500GB harddrives, and Win 7 x64 Enterprise SP1. My primary video card is an ATI FirePro V4800 1GB in a PCIe slot of some speed driving a pair of 23s at 1920x1080 through DisplayPort-HDMI adapters. The secondary card is an NVidia GeForce 8400GS in a PCI slot driving a single 17" at 1280x1024 through DVI. On either of the 23" monitors, windows move smoothly, scroll quickly, and are generally very responsive. On the 17", it's slow, chunky, and when I'm trying to scroll a ton of content, Windows will occasionally suggest I drop to the Windows Basic theme. I've updated drivers for both cards, and I've gotten every Windows update relating to video. Specifically: ATI FirePro Provider: Advanced Micro Devices, Inc Date: 6/22/2014 Version: 13.352.1014.0 NVidia 8400 GS Provider: NVIDIA Date: 7/2/2014 Version: 9.18.13.4052 Unfortunately, new hardware isn't really an option. Is there anything I can do software-wise to speed up the NVidia-driven monitor?

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  • Solaris 11 Launch Blog Carnival Roundup

    - by constant
    Solaris 11 is here! And together with the official launch activities, a lot of Oracle and non-Oracle bloggers contributed helpful and informative blog articles to help your datacenter go to eleven. Here are some notable blog postings, sorted by category for your Solaris 11 blog-reading pleasure: Getting Started/Overview A lot of people speculated that the official launch of Solaris 11 would be on 11/11 (whatever way you want to turn it), but it actually happened two days earlier. Larry Wake himself offers 11 Reasons Why Oracle Solaris 11 11/11 Isn't Being Released on 11/11/11. Then, Larry goes on with a summary: Oracle Solaris 11: The First Cloud OS gives you a short and sweet rundown of what the major new features of Solaris 11 are. Jeff Victor has his own list of What's New in Oracle Solaris 11. A popular Solaris 11 meme is to write a blog post about 11 favourite features: Jim Laurent's 11 Reasons to Love Solaris 11, Darren Moffat's 11 Favourite Solaris 11 Features, Mike Gerdt's 11 of My Favourite Things! are just three examples of "11 Favourite Things..." type blog posts, I'm sure many more will follow... More official overview content for Solaris 11 is available from the Oracle Tech Network Solaris 11 Portal. Also, check out Rick Ramsey's blog post Solaris 11 Resources for System Administrators on the OTN Blog and his secret 5 Commands That Make Solaris Administration Easier post from the OTN Garage. (Automatic) Installation and the Image Packaging System (IPS) The brand new Image Packaging System (IPS) and the Automatic Installer (IPS), together with numerous other install/packaging/boot/patching features are among the most significant improvements in Solaris 11. But before installing, you may wonder whether Solaris 11 will support your particular set of hardware devices. Again, the OTN Garage comes to the rescue with Rick Ramsey's post How to Find Out Which Devices Are Supported By Solaris 11. Included is a useful guide to all the first steps to get your Solaris 11 system up and running. Tim Foster had a whole handful of blog posts lined up for the launch, teaching you everything you need to know about IPS but didn't dare to ask: The IPS System Repository, IPS Self-assembly - Part 1: Overlays and Part 2: Multiple Packages Delivering Configuration. Watch out for more IPS posts from Tim! If installing packages or upgrading your system from the net makes you uneasy, then you're not alone: Jim Laurent will tech you how Building a Solaris 11 Repository Without Network Connection will make your life easier. Many of you have already peeked into the future by installing Solaris 11 Express. If you're now wondering whether you can upgrade or whether a fresh install is necessary, then check out Alan Hargreaves's post Upgrading Solaris 11 Express b151a with support to Solaris 11. The trick is in upgrading your pkg(1M) first. Networking One of the first things to do after installing Solaris 11 (or any operating system for that matter), is to set it up for networking. Solaris 11 comes with the brand new "Network Auto-Magic" feature which can figure out everything by itself. For those cases where you want to exercise a little more control, Solaris 11 left a few people scratching their heads. Fortunately, Tschokko wrote up this cool blog post: Solaris 11 manual IPv4 & IPv6 configuration right after the launch ceremony. Thanks, Tschokko! And Milek points out a long awaited networking feature in Solaris 11 called Solaris 11 - hostmodel, which I know for a fact that many customers have looked forward to: How to "bind" a Solaris 11 system to a specific gateway for specific IP address it is using. Steffen Weiberle teaches us how to tune the Solaris 11 networking stack the proper way: ipadm(1M). No more fiddling with ndd(1M)! Check out his tutorial on Solaris 11 Network Tunables. And if you want to get even deeper into the networking stack, there's nothing better than DTrace. Alan Maguire teaches you in: DTracing TCP Congestion Control how to probe deeply into the Solaris 11 TCP/IP stack, the TCP congestion control part in particular. Don't miss his other DTrace and TCP related blog posts! DTrace And there we are: DTrace, the king of all observability tools. Long time DTrace veteran and co-author of The DTrace book*, Brendan Gregg blogged about Solaris 11 DTrace syscall provider changes. BTW, after you install Solaris 11, check out the DTrace toolkit which is installed by default in /usr/dtrace/DTT. It is chock full of handy DTrace scripts, many of which contributed by Brendan himself! Security Another big theme in Solaris 11, and one that is crucial for the success of any operating system in the Cloud is Security. Here are some notable posts in this category: Darren Moffat starts by showing us how to completely get rid of root: Completely Disabling Root Logins on Solaris 11. With no root user, there's one major entry point less to worry about. But that's only the start. In Immutable Zones on Encrypted ZFS, Darren shows us how to double the security of your services: First by locking them into the new Immutable Zones feature, then by encrypting their data using the new ZFS encryption feature. And if you're still missing sudo from your Linux days, Darren again has a solution: Password (PAM) caching for Solaris su - "a la sudo". If you're wondering how much compute power all this encryption will cost you, you're in luck: The Solaris X86 AESNI OpenSSL Engine will make sure you'll use your Intel's embedded crypto support to its fullest. And if you own a brand new SPARC T4 machine you're even luckier: It comes with its own SPARC T4 OpenSSL Engine. Dan Anderson's posts show how there really is now excuse not to encrypt any more... Developers Solaris 11 has a lot to offer to developers as well. Ali Bahrami has a series of blog posts that cover diverse developer topics: elffile: ELF Specific File Identification Utility, Using Stub Objects and The Stub Proto: Not Just For Stub Objects Anymore to name a few. BTW, if you're a developer and want to shape the future of Solaris 11, then Vijay Tatkar has a hint for you: Oracle (Sun Systems Group) is hiring! Desktop and Graphics Yes, Solaris 11 is a 100% server OS, but it can also offer a decent desktop environment, especially if you are a developer. Alan Coopersmith starts by discussing S11 X11: ye olde window system in today's new operating system, then Calum Benson shows us around What's new on the Solaris 11 Desktop. Even accessibility is a first-class citizen in the Solaris 11 user interface. Peter Korn celebrates: Accessible Oracle Solaris 11 - released! Performance Gone are the days of "Slowaris", when Solaris was among the few OSes that "did the right thing" while others cut corners just to win benchmarks. Today, Solaris continues doing the right thing, and it delivers the right performance at the same time. Need proof? Check out Brian's BestPerf blog with continuous updates from the benchmarking lab, including Recent Benchmarks Using Oracle Solaris 11! Send Me More Solaris 11 Launch Articles! These are just a few of the more interesting blog articles that came out around the Solaris 11 launch, I'm sure there are many more! Feel free to post a comment below if you find a particularly interesting blog post that hasn't been listed so far and share your enthusiasm for Solaris 11! *Affiliate link: Buy cool stuff and support this blog at no extra cost. We both win! var flattr_uid = '26528'; var flattr_tle = 'Solaris 11 Launch Blog Carnival Roundup'; var flattr_dsc = '<strong>Solaris 11 is here!</strong>And together with the official launch activities, a lot of Oracle and non-Oracle bloggers contributed helpful and informative blog articles to help your datacenter <a href="http://en.wikipedia.org/wiki/Up_to_eleven">go to eleven</a>.Here are some notable blog postings, sorted by category for your Solaris 11 blog-reading pleasure:'; var flattr_tag = 'blogging,digest,Oracle,Solaris,solaris,solaris 11'; var flattr_cat = 'text'; var flattr_url = 'http://constantin.glez.de/blog/2011/11/solaris-11-launch-blog-carnival-roundup'; var flattr_lng = 'en_GB'

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  • General monitoring for SQL Server Analysis Services using Performance Monitor

    - by Testas
    A recent customer engagement required a setup of a monitoring solution for SSAS, due to the time restrictions placed upon this, native Windows Performance Monitor (Perfmon) and SQL Server Profiler Monitoring Tools was used as using a third party tool would have meant the customer providing an additional monitoring server that was not available.I wanted to outline the performance monitoring counters that was used to monitor the system on which SSAS was running. Due to the slow query performance that was occurring during certain scenarios, perfmon was used to establish if any pressure was being placed on the Disk, CPU or Memory subsystem when concurrent connections access the same query, and Profiler to pinpoint how the query was being managed within SSAS, profiler I will leave for another blogThis guide is not designed to provide a definitive list of what should be used when monitoring SSAS, different situations may require the addition or removal of counters as presented by the situation. However I hope that it serves as a good basis for starting your monitoring of SSAS. I would also like to acknowledge Chris Webb’s awesome chapters from “Expert Cube Development” that also helped shape my monitoring strategy:http://cwebbbi.spaces.live.com/blog/cns!7B84B0F2C239489A!6657.entrySimulating ConnectionsTo simulate the additional connections to the SSAS server whilst monitoring, I used ascmd to simulate multiple connections to the typical and worse performing queries that were identified by the customer. A similar sript can be downloaded from codeplex at http://www.codeplex.com/SQLSrvAnalysisSrvcs.     File name: ASCMD_StressTestingScripts.zip. Performance MonitorWithin performance monitor,  a counter log was created that contained the list of counters below. The important point to note when running the counter log is that the RUN AS property within the counter log properties should be changed to an account that has rights to the SSAS instance when monitoring MSAS counters. Failure to do so means that the counter log runs under the system account, no errors or warning are given while running the counter log, and it is not until you need to view the MSAS counters that they will not be displayed if run under the default account that has no right to SSAS. If your connection simulation takes hours, this could prove quite frustrating if not done beforehand JThe counters used……  Object Counter Instance Justification System Processor Queue legnth N/A Indicates how many threads are waiting for execution against the processor. If this counter is consistently higher than around 5 when processor utilization approaches 100%, then this is a good indication that there is more work (active threads) available (ready for execution) than the machine's processors are able to handle. System Context Switches/sec N/A Measures how frequently the processor has to switch from user- to kernel-mode to handle a request from a thread running in user mode. The heavier the workload running on your machine, the higher this counter will generally be, but over long term the value of this counter should remain fairly constant. If this counter suddenly starts increasing however, it may be an indicating of a malfunctioning device, especially if the Processor\Interrupts/sec\(_Total) counter on your machine shows a similar unexplained increase Process % Processor Time sqlservr Definately should be used if Processor\% Processor Time\(_Total) is maxing at 100% to assess the effect of the SQL Server process on the processor Process % Processor Time msmdsrv Definately should be used if Processor\% Processor Time\(_Total) is maxing at 100% to assess the effect of the SQL Server process on the processor Process Working Set sqlservr If the Memory\Available bytes counter is decreaing this counter can be run to indicate if the process is consuming larger and larger amounts of RAM. Process(instance)\Working Set measures the size of the working set for each process, which indicates the number of allocated pages the process can address without generating a page fault. Process Working Set msmdsrv If the Memory\Available bytes counter is decreaing this counter can be run to indicate if the process is consuming larger and larger amounts of RAM. Process(instance)\Working Set measures the size of the working set for each process, which indicates the number of allocated pages the process can address without generating a page fault. Processor % Processor Time _Total and individual cores measures the total utilization of your processor by all running processes. If multi-proc then be mindful only an average is provided Processor % Privileged Time _Total To see how the OS is handling basic IO requests. If kernel mode utilization is high, your machine is likely underpowered as it's too busy handling basic OS housekeeping functions to be able to effectively run other applications. Processor % User Time _Total To see how the applications is interacting from a processor perspective, a high percentage utilisation determine that the server is dealing with too many apps and may require increasing thje hardware or scaling out Processor Interrupts/sec _Total  The average rate, in incidents per second, at which the processor received and serviced hardware interrupts. Shoulr be consistant over time but a sudden unexplained increase could indicate a device malfunction which can be confirmed using the System\Context Switches/sec counter Memory Pages/sec N/A Indicates the rate at which pages are read from or written to disk to resolve hard page faults. This counter is a primary indicator of the kinds of faults that cause system-wide delays, this is the primary counter to watch for indication of possible insufficient RAM to meet your server's needs. A good idea here is to configure a perfmon alert that triggers when the number of pages per second exceeds 50 per paging disk on your system. May also want to see the configuration of the page file on the Server Memory Available Mbytes N/A is the amount of physical memory, in bytes, available to processes running on the computer. if this counter is greater than 10% of the actual RAM in your machine then you probably have more than enough RAM. monitor it regularly to see if any downward trend develops, and set an alert to trigger if it drops below 2% of the installed RAM. Physical Disk Disk Transfers/sec for each physical disk If it goes above 10 disk I/Os per second then you've got poor response time for your disk. Physical Disk Idle Time _total If Disk Transfers/sec is above  25 disk I/Os per second use this counter. which measures the percent time that your hard disk is idle during the measurement interval, and if you see this counter fall below 20% then you've likely got read/write requests queuing up for your disk which is unable to service these requests in a timely fashion. Physical Disk Disk queue legnth For the OLAP and SQL physical disk A value that is consistently less than 2 means that the disk system is handling the IO requests against the physical disk Network Interface Bytes Total/sec For the NIC Should be monitored over a period of time to see if there is anb increase/decrease in network utilisation Network Interface Current Bandwidth For the NIC is an estimate of the current bandwidth of the network interface in bits per second (BPS). MSAS 2005: Memory Memory Limit High KB N/A Shows (as a percentage) the high memory limit configured for SSAS in C:\Program Files\Microsoft SQL Server\MSAS10.MSSQLSERVER\OLAP\Config\msmdsrv.ini MSAS 2005: Memory Memory Limit Low KB N/A Shows (as a percentage) the low memory limit configured for SSAS in C:\Program Files\Microsoft SQL Server\MSAS10.MSSQLSERVER\OLAP\Config\msmdsrv.ini MSAS 2005: Memory Memory Usage KB N/A Displays the memory usage of the server process. MSAS 2005: Memory File Store KB N/A Displays the amount of memory that is reserved for the Cache. Note if total memory limit in the msmdsrv.ini is set to 0, no memory is reserved for the cache MSAS 2005: Storage Engine Query Queries from Cache Direct / sec N/A Displays the rate of queries answered from the cache directly MSAS 2005: Storage Engine Query Queries from Cache Filtered / Sec N/A Displays the Rate of queries answered by filtering existing cache entry. MSAS 2005: Storage Engine Query Queries from File / Sec N/A Displays the Rate of queries answered from files. MSAS 2005: Storage Engine Query Average time /query N/A Displays the average time of a query MSAS 2005: Connection Current connections N/A Displays the number of connections against the SSAS instance MSAS 2005: Connection Requests / sec N/A Displays the rate of query requests per second MSAS 2005: Locks Current Lock Waits N/A Displays thhe number of connections waiting on a lock MSAS 2005: Threads Query Pool job queue Length N/A The number of queries in the job queue MSAS 2005:Proc Aggregations Temp file bytes written/sec N/A Shows the number of bytes of data processed in a temporary file MSAS 2005:Proc Aggregations Temp file rows written/sec N/A Shows the number of bytes of data processed in a temporary file 

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  • MySQL Cluster 7.2: Over 8x Higher Performance than Cluster 7.1

    - by Mat Keep
    0 0 1 893 5092 Homework 42 11 5974 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} Summary The scalability enhancements delivered by extensions to multi-threaded data nodes enables MySQL Cluster 7.2 to deliver over 8x higher performance than the previous MySQL Cluster 7.1 release on a recent benchmark What’s New in MySQL Cluster 7.2 MySQL Cluster 7.2 was released as GA (Generally Available) in February 2012, delivering many enhancements to performance on complex queries, new NoSQL Key / Value API, cross-data center replication and ease-of-use. These enhancements are summarized in the Figure below, and detailed in the MySQL Cluster New Features whitepaper Figure 1: Next Generation Web Services, Cross Data Center Replication and Ease-of-Use Once of the key enhancements delivered in MySQL Cluster 7.2 is extensions made to the multi-threading processes of the data nodes. Multi-Threaded Data Node Extensions The MySQL Cluster 7.2 data node is now functionally divided into seven thread types: 1) Local Data Manager threads (ldm). Note – these are sometimes also called LQH threads. 2) Transaction Coordinator threads (tc) 3) Asynchronous Replication threads (rep) 4) Schema Management threads (main) 5) Network receiver threads (recv) 6) Network send threads (send) 7) IO threads Each of these thread types are discussed in more detail below. MySQL Cluster 7.2 increases the maximum number of LDM threads from 4 to 16. The LDM contains the actual data, which means that when using 16 threads the data is more heavily partitioned (this is automatic in MySQL Cluster). Each LDM thread maintains its own set of data partitions, index partitions and REDO log. The number of LDM partitions per data node is not dynamically configurable, but it is possible, however, to map more than one partition onto each LDM thread, providing flexibility in modifying the number of LDM threads. The TC domain stores the state of in-flight transactions. This means that every new transaction can easily be assigned to a new TC thread. Testing has shown that in most cases 1 TC thread per 2 LDM threads is sufficient, and in many cases even 1 TC thread per 4 LDM threads is also acceptable. Testing also demonstrated that in some instances where the workload needed to sustain very high update loads it is necessary to configure 3 to 4 TC threads per 4 LDM threads. In the previous MySQL Cluster 7.1 release, only one TC thread was available. This limit has been increased to 16 TC threads in MySQL Cluster 7.2. The TC domain also manages the Adaptive Query Localization functionality introduced in MySQL Cluster 7.2 that significantly enhanced complex query performance by pushing JOIN operations down to the data nodes. Asynchronous Replication was separated into its own thread with the release of MySQL Cluster 7.1, and has not been modified in the latest 7.2 release. To scale the number of TC threads, it was necessary to separate the Schema Management domain from the TC domain. The schema management thread has little load, so is implemented with a single thread. The Network receiver domain was bound to 1 thread in MySQL Cluster 7.1. With the increase of threads in MySQL Cluster 7.2 it is also necessary to increase the number of recv threads to 8. This enables each receive thread to service one or more sockets used to communicate with other nodes the Cluster. The Network send thread is a new thread type introduced in MySQL Cluster 7.2. Previously other threads handled the sending operations themselves, which can provide for lower latency. To achieve highest throughput however, it has been necessary to create dedicated send threads, of which 8 can be configured. It is still possible to configure MySQL Cluster 7.2 to a legacy mode that does not use any of the send threads – useful for those workloads that are most sensitive to latency. The IO Thread is the final thread type and there have been no changes to this domain in MySQL Cluster 7.2. Multiple IO threads were already available, which could be configured to either one thread per open file, or to a fixed number of IO threads that handle the IO traffic. Except when using compression on disk, the IO threads typically have a very light load. Benchmarking the Scalability Enhancements The scalability enhancements discussed above have made it possible to scale CPU usage of each data node to more than 5x of that possible in MySQL Cluster 7.1. In addition, a number of bottlenecks have been removed, making it possible to scale data node performance by even more than 5x. Figure 2: MySQL Cluster 7.2 Delivers 8.4x Higher Performance than 7.1 The flexAsynch benchmark was used to compare MySQL Cluster 7.2 performance to 7.1 across an 8-node Intel Xeon x5670-based cluster of dual socket commodity servers (6 cores each). As the results demonstrate, MySQL Cluster 7.2 delivers over 8x higher performance per data nodes than MySQL Cluster 7.1. More details of this and other benchmarks will be published in a new whitepaper – coming soon, so stay tuned! In a following blog post, I’ll provide recommendations on optimum thread configurations for different types of server processor. You can also learn more from the Best Practices Guide to Optimizing Performance of MySQL Cluster Conclusion MySQL Cluster has achieved a range of impressive benchmark results, and set in context with the previous 7.1 release, is able to deliver over 8x higher performance per node. As a result, the multi-threaded data node extensions not only serve to increase performance of MySQL Cluster, they also enable users to achieve significantly improved levels of utilization from current and future generations of massively multi-core, multi-thread processor designs.

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  • Disk Drive not working

    - by user287681
    The CD/DVD drive on my sisters' (I'm helping her shift from Win. XP (now officially deprecated by Microsoft) to Ubuntu) system. Now, it may end up being a failed attempt, all together (Almost the whole last year (when she's been on XP) the disk drive hasn't (not even powering on) been working.), I just want to make sure I've explored every remote possibility. Because I figure, "Huh, now that I've got Ubuntu running, instead of XP, that (just) might make a difference.". I have tried using the sudo lshw command in the terminal, to (seemingly) no avil, but, who knows, you might be able to make something out of it. Here's the output: kyra@kyra-Satellite-P105:~$ sudo lshw [sudo] password for kyra: kyra-satellite-p105 description: Notebook product: Satellite P105 () vendor: TOSHIBA version: PSPA0U-0TN01M serial: 96084354W width: 64 bits capabilities: smbios-2.4 dmi-2.4 vsyscall32 configuration: administrator_password=disabled boot=oem-specific chassis=notebook frontpanel_password=unknown keyboard_password=unknown power-on_password=disabled uuid=00900559-F88E-D811-82E0-00163680E992 *-core description: Motherboard product: Satellite P105 vendor: TOSHIBA physical id: 0 version: Not Applicable serial: 1234567890 *-firmware description: BIOS vendor: TOSHIBA physical id: 0 version: V4.70 date: 01/19/20092 size: 92KiB capabilities: isa pci pcmcia pnp upgrade shadowing escd cdboot acpi usb biosbootspecification *-cpu description: CPU product: Intel(R) Core(TM)2 CPU T5500 @ 1.66GHz vendor: Intel Corp. physical id: 4 bus info: cpu@0 version: Intel(R) Core(TM)2 CPU T5 slot: U2E1 size: 1667MHz capacity: 1667MHz width: 64 bits clock: 166MHz capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx x86-64 constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dtherm cpufreq *-cache:0 description: L1 cache physical id: 5 slot: L1 Cache size: 16KiB capacity: 16KiB capabilities: asynchronous internal write-back *-cache:1 description: L2 cache physical id: 6 slot: L2 Cache size: 2MiB capabilities: burst external write-back *-memory description: System Memory physical id: c slot: System board or motherboard size: 2GiB capacity: 3GiB *-bank:0 description: SODIMM DDR2 Synchronous physical id: 0 slot: M1 size: 1GiB width: 64 bits *-bank:1 description: SODIMM DDR2 Synchronous physical id: 1 slot: M2 size: 1GiB width: 64 bits *-pci description: Host bridge product: Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 03 width: 32 bits clock: 33MHz configuration: driver=agpgart-intel resources: irq:0 *-display:0 description: VGA compatible controller product: Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 03 width: 32 bits clock: 33MHz capabilities: msi pm vga_controller bus_master cap_list rom configuration: driver=i915 latency=0 resources: irq:16 memory:d0200000-d027ffff ioport:1800(size=8) memory:c0000000-cfffffff memory:d0300000-d033ffff *-display:1 UNCLAIMED description: Display controller product: Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller vendor: Intel Corporation physical id: 2.1 bus info: pci@0000:00:02.1 version: 03 width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list configuration: latency=0 resources: memory:d0280000-d02fffff *-multimedia description: Audio device product: NM10/ICH7 Family High Definition Audio Controller vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 02 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:44 memory:d0340000-d0343fff *-pci:0 description: PCI bridge product: NM10/ICH7 Family PCI Express Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: 02 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:40 ioport:3000(size=4096) memory:84000000-841fffff ioport:84200000(size=2097152) *-pci:1 description: PCI bridge product: NM10/ICH7 Family PCI Express Port 2 vendor: Intel Corporation physical id: 1c.1 bus info: pci@0000:00:1c.1 version: 02 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:41 ioport:4000(size=4096) memory:84400000-846fffff ioport:84700000(size=2097152) *-network description: Wireless interface product: PRO/Wireless 3945ABG [Golan] Network Connection vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 02 serial: 00:13:02:d6:d2:35 width: 32 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwl3945 driverversion=3.13.0-29-generic firmware=15.32.2.9 ip=10.110.20.157 latency=0 link=yes multicast=yes wireless=IEEE 802.11abg resources: irq:43 memory:84400000-84400fff *-pci:2 description: PCI bridge product: NM10/ICH7 Family PCI Express Port 3 vendor: Intel Corporation physical id: 1c.2 bus info: pci@0000:00:1c.2 version: 02 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:42 ioport:5000(size=4096) memory:84900000-84afffff ioport:84b00000(size=2097152) *-usb:0 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #1 vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:23 ioport:1820(size=32) *-usb:1 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #2 vendor: Intel Corporation physical id: 1d.1 bus info: pci@0000:00:1d.1 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:19 ioport:1840(size=32) *-usb:2 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #3 vendor: Intel Corporation physical id: 1d.2 bus info: pci@0000:00:1d.2 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:18 ioport:1860(size=32) *-usb:3 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #4 vendor: Intel Corporation physical id: 1d.3 bus info: pci@0000:00:1d.3 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:16 ioport:1880(size=32) *-usb:4 description: USB controller product: NM10/ICH7 Family USB2 EHCI Controller vendor: Intel Corporation physical id: 1d.7 bus info: pci@0000:00:1d.7 version: 02 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci-pci latency=0 resources: irq:23 memory:d0544000-d05443ff *-pci:3 description: PCI bridge product: 82801 Mobile PCI Bridge vendor: Intel Corporation physical id: 1e bus info: pci@0000:00:1e.0 version: e2 width: 32 bits clock: 33MHz capabilities: pci subtractive_decode bus_master cap_list resources: ioport:2000(size=4096) memory:d0000000-d00fffff ioport:80000000(size=67108864) *-pcmcia description: CardBus bridge product: PCIxx12 Cardbus Controller vendor: Texas Instruments physical id: 4 bus info: pci@0000:0a:04.0 version: 00 width: 32 bits clock: 33MHz capabilities: pcmcia bus_master cap_list configuration: driver=yenta_cardbus latency=176 maxlatency=5 mingnt=192 resources: irq:17 memory:d0004000-d0004fff ioport:2400(size=256) ioport:2800(size=256) memory:80000000-83ffffff memory:88000000-8bffffff *-firewire description: FireWire (IEEE 1394) product: PCIxx12 OHCI Compliant IEEE 1394 Host Controller vendor: Texas Instruments physical id: 4.1 bus info: pci@0000:0a:04.1 version: 00 width: 32 bits clock: 33MHz capabilities: pm ohci bus_master cap_list configuration: driver=firewire_ohci latency=64 maxlatency=4 mingnt=3 resources: irq:17 memory:d0007000-d00077ff memory:d0000000-d0003fff *-storage description: Mass storage controller product: 5-in-1 Multimedia Card Reader (SD/MMC/MS/MS PRO/xD) vendor: Texas Instruments physical id: 4.2 bus info: pci@0000:0a:04.2 version: 00 width: 32 bits clock: 33MHz capabilities: storage pm bus_master cap_list configuration: driver=tifm_7xx1 latency=64 maxlatency=4 mingnt=7 resources: irq:17 memory:d0005000-d0005fff *-generic description: SD Host controller product: PCIxx12 SDA Standard Compliant SD Host Controller vendor: Texas Instruments physical id: 4.3 bus info: pci@0000:0a:04.3 version: 00 width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list configuration: driver=sdhci-pci latency=64 maxlatency=4 mingnt=7 resources: irq:17 memory:d0007800-d00078ff *-network description: Ethernet interface product: PRO/100 VE Network Connection vendor: Intel Corporation physical id: 8 bus info: pci@0000:0a:08.0 logical name: eth0 version: 02 serial: 00:16:36:80:e9:92 size: 10Mbit/s capacity: 100Mbit/s width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e100 driverversion=3.5.24-k2-NAPI duplex=half latency=64 link=no maxlatency=56 mingnt=8 multicast=yes port=MII speed=10Mbit/s resources: irq:20 memory:d0006000-d0006fff ioport:2000(size=64) *-isa description: ISA bridge product: 82801GBM (ICH7-M) LPC Interface Bridge vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 02 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: driver=lpc_ich latency=0 resources: irq:0 *-ide description: IDE interface product: 82801GBM/GHM (ICH7-M Family) SATA Controller [IDE mode] vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 version: 02 width: 32 bits clock: 66MHz capabilities: ide pm bus_master cap_list configuration: driver=ata_piix latency=0 resources: irq:19 ioport:1f0(size=8) ioport:3f6 ioport:170(size=8) ioport:376 ioport:18b0(size=16) *-serial UNCLAIMED description: SMBus product: NM10/ICH7 Family SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 02 width: 32 bits clock: 33MHz configuration: latency=0 resources: ioport:18c0(size=32) *-scsi physical id: 1 logical name: scsi0 capabilities: emulated *-disk description: ATA Disk product: ST9250421AS vendor: Seagate physical id: 0.0.0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: SD13 serial: 5TH0B2HB size: 232GiB (250GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 sectorsize=512 signature=000d7fd5 *-volume:0 description: EXT4 volume vendor: Linux physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 logical name: / version: 1.0 serial: 13bb4bdd-8cc9-40e2-a490-dbe436c2a02d size: 230GiB capacity: 230GiB capabilities: primary bootable journaled extended_attributes large_files huge_files dir_nlink recover extents ext4 ext2 initialized configuration: created=2014-06-01 17:37:01 filesystem=ext4 lastmountpoint=/ modified=2014-06-01 21:15:21 mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,data=ordered mounted=2014-06-01 21:15:21 state=mounted *-volume:1 description: Extended partition physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 size: 2037MiB capacity: 2037MiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume description: Linux swap / Solaris partition physical id: 5 logical name: /dev/sda5 capacity: 2037MiB capabilities: nofs *-remoteaccess UNCLAIMED vendor: Intel physical id: 1 capabilities: inbound kyra@kyra-Satellite-P105:~$

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  • DTracing TCP congestion control

    - by user12820842
    In a previous post, I showed how we can use DTrace to probe TCP receive and send window events. TCP receive and send windows are in effect both about flow-controlling how much data can be received - the receive window reflects how much data the local TCP is prepared to receive, while the send window simply reflects the size of the receive window of the peer TCP. Both then represent flow control as imposed by the receiver. However, consider that without the sender imposing flow control, and a slow link to a peer, TCP will simply fill up it's window with sent segments. Dealing with multiple TCP implementations filling their peer TCP's receive windows in this manner, busy intermediate routers may drop some of these segments, leading to timeout and retransmission, which may again lead to drops. This is termed congestion, and TCP has multiple congestion control strategies. We can see that in this example, we need to have some way of adjusting how much data we send depending on how quickly we receive acknowledgement - if we get ACKs quickly, we can safely send more segments, but if acknowledgements come slowly, we should proceed with more caution. More generally, we need to implement flow control on the send side also. Slow Start and Congestion Avoidance From RFC2581, let's examine the relevant variables: "The congestion window (cwnd) is a sender-side limit on the amount of data the sender can transmit into the network before receiving an acknowledgment (ACK). Another state variable, the slow start threshold (ssthresh), is used to determine whether the slow start or congestion avoidance algorithm is used to control data transmission" Slow start is used to probe the network's ability to handle transmission bursts both when a connection is first created and when retransmission timers fire. The latter case is important, as the fact that we have effectively lost TCP data acts as a motivator for re-probing how much data the network can handle from the sending TCP. The congestion window (cwnd) is initialized to a relatively small value, generally a low multiple of the sending maximum segment size. When slow start kicks in, we will only send that number of bytes before waiting for acknowledgement. When acknowledgements are received, the congestion window is increased in size until cwnd reaches the slow start threshold ssthresh value. For most congestion control algorithms the window increases exponentially under slow start, assuming we receive acknowledgements. We send 1 segment, receive an ACK, increase the cwnd by 1 MSS to 2*MSS, send 2 segments, receive 2 ACKs, increase the cwnd by 2*MSS to 4*MSS, send 4 segments etc. When the congestion window exceeds the slow start threshold, congestion avoidance is used instead of slow start. During congestion avoidance, the congestion window is generally updated by one MSS for each round-trip-time as opposed to each ACK, and so cwnd growth is linear instead of exponential (we may receive multiple ACKs within a single RTT). This continues until congestion is detected. If a retransmit timer fires, congestion is assumed and the ssthresh value is reset. It is reset to a fraction of the number of bytes outstanding (unacknowledged) in the network. At the same time the congestion window is reset to a single max segment size. Thus, we initiate slow start until we start receiving acknowledgements again, at which point we can eventually flip over to congestion avoidance when cwnd ssthresh. Congestion control algorithms differ most in how they handle the other indication of congestion - duplicate ACKs. A duplicate ACK is a strong indication that data has been lost, since they often come from a receiver explicitly asking for a retransmission. In some cases, a duplicate ACK may be generated at the receiver as a result of packets arriving out-of-order, so it is sensible to wait for multiple duplicate ACKs before assuming packet loss rather than out-of-order delivery. This is termed fast retransmit (i.e. retransmit without waiting for the retransmission timer to expire). Note that on Oracle Solaris 11, the congestion control method used can be customized. See here for more details. In general, 3 or more duplicate ACKs indicate packet loss and should trigger fast retransmit . It's best not to revert to slow start in this case, as the fact that the receiver knew it was missing data suggests it has received data with a higher sequence number, so we know traffic is still flowing. Falling back to slow start would be excessive therefore, so fast recovery is used instead. Observing slow start and congestion avoidance The following script counts TCP segments sent when under slow start (cwnd ssthresh). #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::connect-request / start[args[1]-cs_cid] == 0/ { start[args[1]-cs_cid] = 1; } tcp:::send / start[args[1]-cs_cid] == 1 && args[3]-tcps_cwnd tcps_cwnd_ssthresh / { @c["Slow start", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } tcp:::send / start[args[1]-cs_cid] == 1 && args[3]-tcps_cwnd args[3]-tcps_cwnd_ssthresh / { @c["Congestion avoidance", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } As we can see the script only works on connections initiated since it is started (using the start[] associative array with the connection ID as index to set whether it's a new connection (start[cid] = 1). From there we simply differentiate send events where cwnd ssthresh (congestion avoidance). Here's the output taken when I accessed a YouTube video (where rport is 80) and from an FTP session where I put a large file onto a remote system. # dtrace -s tcp_slow_start.d ^C ALGORITHM RADDR RPORT #SEG Slow start 10.153.125.222 20 6 Slow start 138.3.237.7 80 14 Slow start 10.153.125.222 21 18 Congestion avoidance 10.153.125.222 20 1164 We see that in the case of the YouTube video, slow start was exclusively used. Most of the segments we sent in that case were likely ACKs. Compare this case - where 14 segments were sent using slow start - to the FTP case, where only 6 segments were sent before we switched to congestion avoidance for 1164 segments. In the case of the FTP session, the FTP data on port 20 was predominantly sent with congestion avoidance in operation, while the FTP session relied exclusively on slow start. For the default congestion control algorithm - "newreno" - on Solaris 11, slow start will increase the cwnd by 1 MSS for every acknowledgement received, and by 1 MSS for each RTT in congestion avoidance mode. Different pluggable congestion control algorithms operate slightly differently. For example "highspeed" will update the slow start cwnd by the number of bytes ACKed rather than the MSS. And to finish, here's a neat oneliner to visually display the distribution of congestion window values for all TCP connections to a given remote port using a quantization. In this example, only port 80 is in use and we see the majority of cwnd values for that port are in the 4096-8191 range. # dtrace -n 'tcp:::send { @q[args[4]-tcp_dport] = quantize(args[3]-tcps_cwnd); }' dtrace: description 'tcp:::send ' matched 10 probes ^C 80 value ------------- Distribution ------------- count -1 | 0 0 |@@@@@@ 5 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 0 512 | 0 1024 | 0 2048 |@@@@@@@@@ 8 4096 |@@@@@@@@@@@@@@@@@@@@@@@@@@ 23 8192 | 0

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  • DBA Best Practices - A Blog Series: Episode 1 - Backups

    - by Argenis
      This blog post is part of the DBA Best Practices series, on which various topics of concern for daily database operations are discussed. Your feedback and comments are very much welcome, so please drop by the comments section and be sure to leave your thoughts on the subject. Morning Coffee When I was a DBA, the first thing I did when I sat down at my desk at work was checking that all backups had completed successfully. It really was more of a ritual, since I had a dual system in place to check for backup completion: 1) the scheduled agent jobs to back up the databases were set to alert the NOC in failure, and 2) I had a script run from a central server every so often to check for any backup failures. Why the redundancy, you might ask. Well, for one I was once bitten by the fact that database mail doesn't work 100% of the time. Potential causes for failure include issues on the SMTP box that relays your server email, firewall problems, DNS issues, etc. And so to be sure that my backups completed fine, I needed to rely on a mechanism other than having the servers do the taking - I needed to interrogate the servers and ask each one if an issue had occurred. This is why I had a script run every so often. Some of you might have monitoring tools in place like Microsoft System Center Operations Manager (SCOM) or similar 3rd party products that would track all these things for you. But at that moment, we had no resort but to write our own Powershell scripts to do it. Now it goes without saying that if you don't have backups in place, you might as well find another career. Your most sacred job as a DBA is to protect the data from a disaster, and only properly safeguarded backups can offer you peace of mind here. "But, we have a cluster...we don't need backups" Sadly I've heard this line more than I would have liked to. You need to understand that a cluster is comprised of shared storage, and that is precisely your single point of failure. A cluster will protect you from an issue at the Operating System level, and also under an outage of any SQL-related service or dependent devices. But it will most definitely NOT protect you against corruption, nor will it protect you against somebody deleting data from a table - accidentally or otherwise. Backup, fine. How often do I take a backup? The answer to this is something you will hear frequently when working with databases: it depends. What does it depend on? For one, you need to understand how much data your business is willing to lose. This is what's called Recovery Point Objective, or RPO. If you don't know how much data your business is willing to lose, you need to have an honest and realistic conversation about data loss expectations with your customers, internal or external. From my experience, their first answer to the question "how much data loss can you withstand?" will be "zero". In that case, you will need to explain how zero data loss is very difficult and very costly to achieve, even in today's computing environments. Do you want to go ahead and take full backups of all your databases every hour, or even every day? Probably not, because of the impact that taking a full backup can have on a system. That's what differential and transaction log backups are for. Have I answered the question of how often to take a backup? No, and I did that on purpose. You need to think about how much time you have to recover from any event that requires you to restore your databases. This is what's called Recovery Time Objective. Again, if you go ask your customer how long of an outage they can withstand, at first you will get a completely unrealistic number - and that will be your starting point for discussing a solution that is cost effective. The point that I'm trying to get across is that you need to have a plan. This plan needs to be practiced, and tested. Like a football playbook, you need to rehearse the moves you'll perform when the time comes. How often is up to you, and the objective is that you feel better about yourself and the steps you need to follow when emergency strikes. A backup is nothing more than an untested restore Backups are files. Files are prone to corruption. Put those two together and realize how you feel about those backups sitting on that network drive. When was the last time you restored any of those? Restoring your backups on another box - that, by the way, doesn't have to match the specs of your production server - will give you two things: 1) peace of mind, because now you know that your backups are good and 2) a place to offload your consistency checks with DBCC CHECKDB or any of the other DBCC commands like CHECKTABLE or CHECKCATALOG. This is a great strategy for VLDBs that cannot withstand the additional load created by the consistency checks. If you choose to offload your consistency checks to another server though, be sure to run DBCC CHECKDB WITH PHYSICALONLY on the production server, and if you're using SQL Server 2008 R2 SP1 CU4 and above, be sure to enable traceflags 2562 and/or 2549, which will speed up the PHYSICALONLY checks further - you can read more about this enhancement here. Back to the "How Often" question for a second. If you have the disk, and the network latency, and the system resources to do so, why not backup the transaction log often? As in, every 5 minutes, or even less than that? There's not much downside to doing it, as you will have to clear the log with a backup sooner than later, lest you risk running out space on your tlog, or even your drive. The one drawback to this approach is that you will have more files to deal with at restore time, and processing each file will add a bit of extra time to the entire process. But it might be worth that time knowing that you minimized the amount of data lost. Again, test your plan to make sure that it matches your particular needs. Where to back up to? Network share? Locally? SAN volume? This is another topic where everybody has a favorite choice. So, I'll stick to mentioning what I like to do and what I consider to be the best practice in this regard. I like to backup to a SAN volume, i.e., a drive that actually lives in the SAN, and can be easily attached to another server in a pinch, saving you valuable time - you wouldn't need to restore files on the network (slow) or pull out drives out a dead server (been there, done that, it’s also slow!). The key is to have a copy of those backup files made quickly, and, if at all possible, to a remote target on a different datacenter - or even the cloud. There are plenty of solutions out there that can help you put such a solution together. That right there is the first step towards a practical Disaster Recovery plan. But there's much more to DR, and that's material for a different blog post in this series.

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