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  • Boot records messed on dual boot (win7 and ubuntu) machine with SSD and HDD

    - by Michael
    i have a lenovo ideapad y570 with two hard drives: SSD and normal HDD both managed by RapidDrive and windows 7 pre-installed. First, i have shrunk my 500 GB HDD a little bit to make some place for a linux installation. Then i installed linux mint 12 to it, also installed grub onto the drive (dev/sdb). Installation programm has not allowed me to install grub on sda. Then i replaced linux mint with ubuntu 12.04 but installed grub onto the SSD (which is dev/sda and was the default-option). After that i could boot into my windows, only ubuntu worked. So i did a research, and tried: rewriting mbr of windows into sda1, reinstalling grub, replacing grub2 with grub-legacy, and now i think my partitions table are totally messed. Here is fdisk -l output: ubuntu@ubuntu:~$ sudo fdisk -l Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sda1 * 2048 411647 204800 7 HPFS/NTFS/exFAT /dev/sda2 411648 1009430959 504509656 7 HPFS/NTFS/exFAT Disk /dev/sdb: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x5e5d1cc8 Device Boot Start End Blocks Id System /dev/sdb1 * 1979 884389887 442193954+ 12 Compaq diagnostics /dev/sdb2 884391934 976771071 46189569 5 Extended /dev/sdb5 884391936 937705471 26656768 83 Linux /dev/sdb6 937707520 967006207 14649344 83 Linux /dev/sdb7 967008256 976771071 4881408 82 Linux swap / Solaris I also cant mount any windows partitions to recover data. And when i open gparted, the whole sda-disk appears unallocated and it states "can not have a partition outside the disk!", also the end-sector address of /dev/sda2 confuses me. If i boot from the SSD, it throws some mbr error and wont boot, if i boot from the HDD, i only get the grub bash. How do i restore the partition tables? I can boot only from a live-cd at the machine. Thanks for any help.

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  • Relayout LVM Disk

    - by Tom
    I have an Ubuntu 11.10 system with two 500GB disks. The partition tables look like this: /dev/sda1 primary 465.52GB /dev/sda2 extended 243.17MB -> /dev/sda5 logical 243.14MB /dev/sdb1 primary 465.76GB sda1 and sdb1 are in a single LVM physical volume group containing a single logical volume containing a single logical filesystem which is mounted as /. sda5 is mounted as /boot. The problem comes when I want to upgrade to Ubuntu 12.04, which requires at least 247MB free on /boot. So I need to reduce the size of sda1 so that I can increase the size of sda2 and sda5. How the heck do I do that? I can find how to shrink the logical volume group, but I'm not at all clear on how to clear out the end part of sda1 so that I can reduce the physical volume group. Does pvresize just deal with this automagically? Or is that wild wishful thinking? I guess the alternatives are to back everything up onto something or other and recreate the thing from scratch or find out whether GRUB2 supports using LVM for /boot.

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  • Second CPU missing of Dual Core

    - by Zardoz
    My Lenovo T61 has a dual core CPU. I just noticed that under Ubuntu 10.10 only one CPU is recognized. I know that once both CPUs worked. Not sure since when the second CPU is missing. Maybe since the last kernel update. Currently I am using linux-image-2.6.35-23-generic (for x86_64). What can I do to enable the second CPU again? Here the ouput of /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 23 model name : Intel(R) Core(TM)2 Duo CPU T8100 @ 2.10GHz stepping : 6 cpu MHz : 800.000 cache size : 3072 KB physical id : 0 siblings : 1 core id : 0 cpu cores : 1 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 lahf_lm ida dts tpr_shadow vnmi flexpriority bogomips : 4189.99 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: Any help is welcome. I really need that CPU power for my work here.

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  • How to handle OpenVPN client as a service, when the laptop is physically on the network already?

    - by James
    The Setup I've gotten OpenVPN working on our Windows XP laptops. Users are limited, so I went ahead and set OpenVPN client to run as a service, which is great anyway because that means they are on the VPN before logging in, so login scripts work, plus we can do remote support even if the user can not log in (such as connecting via VNC or resetting passwords). It is also configured to send all traffic over the tunnel, so when, for example, they browse the internet it is just like browsing from our corporate network. The Qestion(s) So, I'm wondering how does the OpenVPN client act when the computer is already physically on the same network as the OpenVPN server? Right now, the client is configured to connect the the public dns name which will resolve to the public ip address which will NOT get reflected back to the OpenVPN server, so it is affectively blocked from connecting to the OpenVPN server while on the network. Is that a good thing? Or will it constantly try to connect, using up system resources and network resources? We will likely have hundreds of laptops regularly on the physical network with this, so it could contribute to a lot of unnecessary network chatter. Alternatively Would it be better to have the firewall reflect the port back to the OpenVPN server and let it connect? Or have our internal dns resolve the name to the private ip and allow them to connect directly? Would traffic then go over the vpn connection (which I do not want, when already on the physical network)? Or is it possible to tell it to ignore the connection when the client and server are already on the same network? TLDR What's a sane way of handling OpenVPN client running as an always-on service when the client and server will often be on the same network?

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  • Can't Connect SQL server - process being used by another process. Conflict with IIS?

    - by shinya
    I'm having problem connecting to MS SQL Server (2012 Express) after accessing a database through IIS (web site). I can access the data through web site no problem, but I can't access the data from any other programs (i.e SSMS) until I reboot the SQL server. It seems that the connection stays open even if I close a browser. Here is error message I'm getting Unable to open the physical file "C:---------". Operating system error 32: "32(The process cannot access the file because it is being used by another process.)". Unable to open the physical file "C:-------". Operating system error 32: "32(The process cannot access the file because it is being used by another process.)". Cannot open user default database. Login failed. Login failed for user 'Myserver\myname'. (.Net SqlClient Data Provider) Server Name: MYPC\SQLEXPRESS Error Number: 5120 Severity: 16 State: 101 Line Number: 65536 I follow the help link and it told me to move TCP before named pipes in the protocol order list. I tried it but it didn't help at all. What is the proper settings on SQL server or IIS in order to release process after closing a browser. How do I avoid getting this error? Thank you for your help

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  • Backtrack, Wi-Fi not working

    - by hradecek
    I've installed Backtrack 5R3 KDE, and I realized that my wireless is not working, but wired is working fine. Here's the lshw output: *-network description: Ethernet interface product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 05 serial: 04:7d:7b:b7:46:f8 size: 100MB/s capacity: 100MB/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl_nic/rtl8105e-1.fw ip=192.168.2.2 latency=0 link=yes multicast=yes port=MII speed=100MB/s resources: irq:42 ioport:2000(size=256) memory:f0404000-f0404fff memory:f0400000-f0403fff lspci output: 00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09) 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 00:14.0 USB Controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04) 00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04) 00:1a.0 USB Controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4) 00:1c.1 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 2 (rev c4) 00:1d.0 USB Controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04) 00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04) 00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA AHCI Controller (rev 04) 00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04) 02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 05)

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  • Windows 2008 R2 DNS cant resolve own SOA

    - by user46742
    We have two Domain Controllers for our network. They both run DHCP, DNS, and ADS. They are both VM's sitting on MS Hyper V Server 2008 on separate physical hosts. We had our primary DC go down a week ago. I upgraded an already existing VM to Primary DC and built a new VM for the secondary. Both DNS servers are running and the SOA is configured correctly for Primary DC 1. However when I run the best practice analyzer it states the server cannot resolve it's own SOA. Check the configuration in the adapter. I checked and they are configured properly. I also went through the DNS entries thoroughly and made sure there was no records of the previous DC that went down. NSLOOKUP resolves the domain and primary dc fine. I also checked the firewalls on the machines and our physical firewall for any deny packets. Any suggestions? I appreciate any help!

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  • Linux RAID: Replacing Failed Drive...permanantly

    - by user137519
    Okay, odd question here. I have a server with RAID 5. A drive failed, in a really physically in a really odd way. On the machine it boots and is seen by the BIOS but...no partition can be seen on the drive consistantly (in and out). 2 out of 3 drives working...I made new spare disk and added it, RAID 5 rebuilt clean. All appears well but...when I reboot it keeps trying to use the 2nd drive which doesn't give any partition data, so of course the RAID 5 gets 2 out of 3...again. The status of my drive is as follows: /dev/sda2:Good /dev/sdb2 (drive has physical problem so no partition data) bad, /dev/sdc2:good /dev/sdd2:good. Every time I reboot the mdadm system seems to keep trying to use /dev/sdb which has physical failure (although spins and is detected). /dev/sdd is the new drive I created. I added /dev/sdd to the raid and it rebuilds the raid but this action isn't memorized upon reboot so it keeps listing /dev/sda and /dev/sdc but doesn't use the perfectly good /dev/sdd until I re-add manually. I've tried removing the dead drive with the mdadm tool, but as it cannot see /dev/sdb paritions it will not fail or remove it (says partition doesn't exist). the /etc/mdadm.conf was automatically made on the original OS install which only lists: DEVICE partitions MAILADDR root ARRAY /dev/md2 super-minor=2 ARRAY /dev/md0 super-minor=0 ARRAY /dev/md1 super-minor=1 Basically just the raids to use on boot. I need to remove this semi-dead drive (/dev/sdb) but I'd prefer to know why this is happening before I do. any ideas or suggestions. I supposed I could attempt to clone/replace /dev/sdb (the partitions on drive show up, then disappear shortly after) but given the partition "chester cat" behaviour this seems risky to me and as I have a working "spare" it seems unnecessary. Thanks in advance for your insight.

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  • Getting dwl-g122 to work on ubuntu

    - by User1
    I have a USB WiFi adapter, D-Link dwl-g122. I'm running Ubuntu 10.4. My laptop has a built-in wireless card that is connecting fine to the router. I plug in the usb and it never really connects. Here are some details: iwconfig wlan1 IEEE 802.11bg ESSID:"\x0B\xE1..." Mode:Managed Frequency:2.457 GHz Access Point: Not-Associated Tx-Power=19 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:on lshw -c network: *-network:1 description: Wireless interface physical id: 3 logical name: wlan1 serial: 00:13:46:8b:xx:xx capabilities: ethernet physical wireless configuration: broadcast=yes multicast=yes wireless=IEEE 802.11bg dmesg [ 1096.814176] wlan1: direct probe to AP xxx (try 1) [ 1096.820960] wlan1: direct probe responded [ 1096.820969] wlan1: authenticate with AP xxx (try 1) [ 1096.823790] wlan1: authenticated [ 1096.823869] wlan1: associate with AP xxx (try 1) [ 1096.827667] wlan1: RX AssocResp from xxx (capab=0x411 status=0 aid=1) [ 1096.827674] wlan1: associated [ 1142.590912] wlan1: deauthenticating from xxx by local choice (reason=3) lsmod|rt2 rt2500usb 19643 0 rt2x00usb 11260 1 rt2500usb rt2x00lib 32133 2 rt2500usb,rt2x00usb mac80211 238896 3 ath5k,rt2x00usb,rt2x00lib cfg80211 148725 4 ath5k,ath,rt2x00lib,mac80211 led_class 3764 3 ath5k,rt2x00lib,sdhci It looks like the driver loads but it doesn't feel like connecting. The behavior is identical even if I blacklist the other wifi card (using an ath5k driver). It's almost like it is using the wrong password or something. Does anyone know what is happening? Is anyone using Ubuntu successful?

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  • A switch and router between the printer and PC that want to print but cannot

    - by Robert Memo
    IP 192.168.1.5 has a wireless connection to a Linksys router (192.168.1.1) which then is connected to a switch. The switch is connected to a server (192.168.0.2). My printer has IP address of 192.168.0.8. Internet connection is fine on 192.168.1.5. Problem 1: IP 192.168.1.5 can not print using printer 192.168.0.8. Problem 2: IP 192.168.1.2 can not access a shared folder on the the server. The reason for connecting this way is that, the server does not release wireless signal. In order to get wireless signal the Router is connected to the switch. The server is a computer server that only has one outgoing LAN port. Plus, due to inconvinience physical locations, I do not have option to change the physical locations and the way it is connected already. I just want the labtops that only have wireless connection to communicate with the printer and the server. I have tried to change the router IP address to 192.168.0.x like the server and printer. It caused problem for the laptop. The router no longer release internet signals. The router does have IP address from the server 192.168.0.5.

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  • Hyper-V VM's cannot access Host resources, and vice-versa

    - by Agent
    I have several Hyper-V vm's running on this Win2008 R2 Server box, and up until a reboot of the host server, all the VM's were able to access shared folders on the host. Now, they can't even ping the host server. From what I've seen, I need to setup an Internal only network through Virtual Network Manager in Hyper-V. I set this up, then tried to enable the Microsoft Virtual Network Switch Protocol option in this Internal Only NIC, but I get popups saying: Your current selection will also disable the following features: Microsoft virtual network switch protocol Which is absolutely stupid, considering the protocol is what I'm ticking the checkbox to Enable! As of now, on the host, I have 2 NICs: Physical - This NIC on the host machine does have the MVNS protocol enabled Virtual Network Adapter - Created through Hyper-V Virtual Network Manager as an External type of network. Trying to enable MVNS on this NIC also produces the error above. I've tried enabling Client for Microsoft Networks on the physical NIC for IPv6, but everytime I do that, all the VMs lose Internet connectivity and I cannot RDP into them. Anything else I can try?

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  • What causes a switch port to receive data not destined for it?

    - by user1693454
    We are having an intermittent fault which is effecting one of our control systems on one of our HP Procurve switches. For some reason, this PLC (10mbit port - 192.168.6.56) which is attached directly to the HP Switch intermittantly start's receiving data which is not destined for it. The data is being sent from a Thecus NAS with latest firmware (192.168.6.218) to a physical IBM Server running Win2003R2 and SAP (192.168.6.225). The problem does not just send to this server, it has been to other physical servers in the past too, but always from the Thecus NAS. I am using a monitor port to wireshark what is going in/out of the PLC - normally there would be about 1mb in/out per 2 or 3 minutes - only a server asking the state of the coils. When the problem occurs, there is a flood of data being put onto the PLC line - in this captured instance, about 67mb in less than a minute. Due to this, there is no way that the PLC can be queried as the port is effectively DOSed, in turn killing part of our factory. I know that having Production on the same vlan as IT is not a good idea - I agree, however it cannot be changed at the moment (will have to wait 3 months), as well as the problem has only started happening in the last 3 months. Here is a screen cap of one of the packets being sent from the Thecus NAS which was captured from the PLC port on the HP Switch: And there are over 700 of these in this one 1024kb file. If anyone has any idea on what could be going on, some help would be greatly appreciated. If you need to know anything more, let me know! Cheers!

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  • How to copy VirtualBox VDI contents to a partition and dual boot the OS from it?

    - by Calmarius
    I'm a Linux user but I keep a compressed Windows XP ISO with me on a pen drive for the case I absolutely need Windows to do something. This works in VirtualBox most of the time. But now I want to play some games, so I would like to run the Windows image natively. My computer don't have CD drive so cannot just burn the ISO and make an install normally. What I trying to do is moving the installed Windows image to a physical NTFS partition on my HDD and set up GRUB to let me dual boot it. I found many tutorials that deal with making VDI to physical drive. But they assume I want to overwrite my entire drive. Moving the raw disk image with dd to the partition resulted in a corrupt partition. I also tried the VMDK trick to use that empty partition and install the Windows on it. Although the text mode phase of the installation finishes without problems, the VM won't work, either crashes and keeps rebooting or just immediately or freezes (depending on how I created the VMDK, with -rawdisk /dev/sda3 or -rawdisk /dev/sda -partition 3).

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  • Almost All Logical Volumes Disappeared - Recovery?

    - by Alex
    We had a hard disc crash of one of two hard discs in a software raid with a LVM on top. The server is running Citrix xenserver. On the hard disk which is still intact, the volume group gets detected well, but only one LV is left. (some hashes replaced by "x") # lvdisplay --- Logical volume --- LV Name /dev/VG_XenStorage-x-x-x-x-408b91acdcae/MGT VG Name VG_XenStorage-x-x-x-x-408b91acdcae LV UUID x-x-x-x-x-x-vQmZ6C LV Write Access read/write LV Status available # open 0 LV Size 4.00 MiB Current LE 1 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 root@rescue ~ # vgdisplay --- Volume group --- VG Name VG_XenStorage-x-x-x-x-408b91acdcae System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 698.62 GiB PE Size 4.00 MiB Total PE 178848 Alloc PE / Size 1 / 4.00 MiB Free PE / Size 178847 / 698.62 GiB VG UUID x-x-x-x-x-x-53w0kL I could understand if a full physical volume is lost - but why only the logical volumes? Is there any explanation for this? Is there any way to recover the logical volumes? EDIT We are here in a rescue system. The problem is that the whole server does not boot (GRUB error 22) What we are trying to do is to access the root filesystem. But everything was in the LVM. We have only this: (parted) print Model: ATA SAMSUNG HD753LJ (scsi) Disk /dev/sdb: 750GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 750GB 750GB primary boot, lvm And this 750GB LVM volume is exactly what we see on top.

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  • LMDE detects a wireless card, but can't use it

    - by Davidos
    LMDE can see my wireless card, and correctly identifies it, but it refuses to let me turn it on through the shiny graphical interface. Is there a way to use the non-shiny terminal to turn on my wireless? One small tidbit I noticed was the stated version; it says the version is 00. I believe that's hexadecimal for 0, which may indicate something screwy with the software. It would be nice if someone could tell me how to figure out how to solve this kind of problem in the future. *-network DISABLED description: Wireless interface product: Centrino Wireless-N 1000 vendor: Intel Corporation physical id: 0 bus info: pci@0000:09:00.0 logical name: wlan0 version: 00 serial: 91:e3:7b:0d:a3:a9 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlagn driverversion=3.0.0-1-amd64 firmware=39.31.5.1 build 35138 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:43 memory:e1d00000-e1d01fff I've tested multiple other network managers, and none of them work. W ireless switch is on, I'm sure it's a driver problem.

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  • Hungry hungry BIOS: why do I have less than 4 GiB of memory?

    - by Rhymoid
    I thought I had 4 GiB of memory, but just to be sure, let's ask the BIOS about that: ?: sudo dmidecode --type 20 # dmidecode 2.12 SMBIOS 2.6 present. Handle 0x000B, DMI type 20, 19 bytes Memory Device Mapped Address Starting Address: 0x00000000000 Ending Address: 0x0007FFFFFFF Range Size: 2 GB Physical Device Handle: 0x000A Memory Array Mapped Address Handle: 0x000E Partition Row Position: Unknown Interleave Position: Unknown Interleaved Data Depth: Unknown Handle 0x000D, DMI type 20, 19 bytes Memory Device Mapped Address Starting Address: 0x00080000000 Ending Address: 0x000FFFFFFFF Range Size: 2 GB Physical Device Handle: 0x000C Memory Array Mapped Address Handle: 0x000E Partition Row Position: Unknown Interleave Position: Unknown Interleaved Data Depth: Unknown Alright, 4 GiB it is. But I can't use all of it: ?: cat /proc/meminfo | head -n 1 MemTotal: 3913452 kB Somehow, somewhere, I lost 274 MiB. Where did 6% of my memory go? Now I know the address ranges in DMI are incorrect, because the ACPI memory map reports usable ranges well beyond the ending address of the second memory module: ?: dmesg | grep -E "BIOS-e820: .* usable" [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009e7ff] usable [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000dee7bfff] usable [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x0000000117ffffff] usable I get pretty much the same info from /proc/iomem (except for the 4 kiB hole 0x000-0xFFF), which also shows that the kernel only accounts for less than 8 MiB. I guess 0x00000000-0x7FFFFFFF is indeed mapped to the first memory module, and 0x80000000-0xDFFFFFFF to part of the second memory module (a bunch of ACPI NVS things live between 0xDEE7C000 and 0xDEF30FFF, and the remaining 16-something MiB of that range are just 'reserved'). I guess the highest 0x18000000 bytes of the second memory module are mapped above the 4 GiB mark. But even then, there are two problems: 128 MiB (0x08000000 bytes, living somewhere between 0xE0000000 and 0xFFFFFFFF) are still completely unaccounted for. To note, my graphics card is on PCI-Express and (allegedly) has 1 GiB dedicated memory, so that shouldn't be the culprit. Did the BIOS screw up in moving the memory, leaving it partially shadowed by MMIO? Even with this mediocre explanation, I only 'found' 128 MiB. But /proc/meminfo is reporting a much larger deficit; where's the other 146 MiB? How does Linux count MemTotal?

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  • VirtualBox bridged network not working as expected

    - by iby chenko
    I am having hard time getting Bridged network to work with VirtualBox. Idea is to have host as well as one or more guests on same LAN. Using NAT (default) I do get access to internet and any node on the LAN when working from one of the VM guests. However, no LAN node including host can access (or ping) guest in VM. I need to be able to use any guest as if it was a physical computer on the network (need to be accessed by any machine on LAN). According to my understanding of the VirtualBox documentation, this should be Bridged mode. I think I set it correctly, well, actually there is not much to it: 1. select Bridged mode in VM network setup 2. select physical NIC of the host to connect bridge to 3. start VM When I do this, each VM does get new IP address that corresponds to LAN settings : 192.168.1.100 192.168.1.102 192.168.1.103 etc. where host is 192.168.1.80 / 255.255.255.0 (IP addresses above 100 are served by DHCP server). This seem to be correct based on what I know about ethernet. From VM I can ping other nodes like 192.168.1.50 etc. and I still get ethernet access. So far so good... But I STILL cannot ping any of the other VMs (running ones of course). I cannot ping them from other VMs, from host or from other nodes on the LAN. Aside from fact that IP addresses handed to guests are now local, this still acts same as NAT. What is going on? What am I missing? Regards, I

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  • RDP with multiple monitors, display preferences get reset?

    - by Martijn Kooij
    Problem: When I connect to my pc at the office via RDP all the application windows I had previously carefully placed on either monitor 1 or 2 will be "scrambled". Either all applications show on monitor 1 and monitor 2 is empty, or they have switched 1 <- 2. Expected behaviour: When I connect I see all the application windows on exactly the same position and in the exact same size as I left them the night before. I have the exact same monitors at home as I have at work: Primary 2560x1440, Secondary 900x1440. Yesterday I tried switching the physical cables on the host machine hoping that the hardware order of the monitors was the difference. But this morning my secondary monitor was completely blank, not even the taskbar (which I had set to ONLY show on the secondary). Somewhere there must be something to help Windows understand which physical monitor is which virtual RDP monitor is which RDP "server" monitor... Are there more options than switching the cables? This one has been bothering me for a long long time now, I hope someone has a solution or workaround for me. Edit I want to use both monitors, so I have checked the "Use all monitors" setting in the RDP client. For example I leave my mail and total commander on the right monitor, and visual studio and Firefox on the left monitor. When I connect to RDP I want to see those applications on the same positions and sizes.

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  • vmware server 64 bit on ubuntu 9.10 64 bit with P2V windows 2003 SBS poor network speed

    - by RobertHC
    configuration is ubuntu 2.6.31-21 64 bit vmware 2.0.2 64 bit last release hardware is core 2 quad with 8GB ram guest is win 2003 server SBS 32 bit Dear friends, we have a converted physical to virtual windows sbs 2003, converted with last converter available nowadays http://www.vmware.com/products/converter/ vCenter converter. Running the P2V 2K3 SBS on vmware server, it does boot fine, but we do note an abnormal CPU activity and a poor lan speed. As attempts we did what follow. We removed all unneeded peripherals, we removed one NIC (phisycal server was 2 nics), we changed the vmx to ged the nic recognized as intel instead than amd, we removed 1 cpu (physical was 2 cpu), we removed anything was reported as failed driver from system events monitor. Nothing to do, no way and funny results. Let's read some tests results. All are made with the same file copied in different source folders. Copying from client side (both directions copy, to/from server) results are i.e. 10 seconds, copying the same files from server side (again from and to server) results are different... from client to server, speed is round about (bit more) 10 seconds, but from server to client direction is slower: double the time. Beeing very fast and launching a simultaneous copy "from server to client"+"from client to server", this made from the server side, results in a stuck traffic... 45 seconds to do the copy. vmware tools are installed and e1000 driver has been updated. With one processor CPU activity is still going up and down but much less than with two. Because of test, we installed win 2k8 STD 64 bit. We repeated all the above tests with exactly the same file result is just one: always 5 seconds (this matches the lan speed) Any idea about this issue is welcome and thank you if any. Kind regards R.

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  • windows server 2003 speed issues

    - by farzinSH
    I have a HP server with windows server 2003 and 50 windows XP clients. Since a week and a half the networks speed suddenly drop 2-3 times per day. It gets so slow that none of the clients could work with the HIS program installed on them. We tried so many different things such as replacing the hubs,switches and even some wires. Every time one of these changes solves the problem and the network goes back to its normal state. I checked everything. Even when I disconnected all the clients from the server and connected it to just one computer the problem still remained for 2 hours. I just narrowed down the problem to the couple of likely speculations as follows: viruses? (Updated Kaspersky running on the server shows none) server hardware failure? Physical memory usage on the server? (Because the last time the problem occurred none of the changes above solved the issue so I restarted the server an checked the physical memory usage which was 2 GBs. But I noticed it's increasing over time to over 9 GBs...the server has 16 GBs of RAM.) I surfed the internet and got nothing. Any help would do us a lot....thanks in advance

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  • Computers on network crashing

    - by Phil Cross
    We have recently upgraded our network to Windows 7 clients with Windows server 2008 servers. The upgrade was completed by the end of September and until now has been fine (apart from the minor bugs). Recently (within the last 2 weeks) we've notice all computers on the network (around 1000) start to slow down to the point their unusable. It starts at about 08:45 and finishes at 09:15. Because of this, we think something may be broadcasting across the network. This happens every day, between these times. I cant use my computer at all at the slowdown peak, and looking at task managers performance graphs, Physical memory is hovering around 35% and CPU usage is at 0-10% (idle) yet still crashing. I've looked on DHCPs server log and cant see anything which stands out. The only change we made prior to the slowdown was installing adobe CS6 on some computers, however the slowdown affects computers without CS6. We have 2 physical machines, each with around 5-7 virtual machines running on them with ample memory. Does anyone have any suggestions as to what we can do to narrow down whats causing the crashes? Any help, suggestions or advice would be appreciated.

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  • Renaming VLAN Interfaces in Linux

    - by rhololkeolke
    I need to know how to rename VLAN interfaces. I'm currently running Ubuntu 11.04. I'm running a networking application that takes frames on one interface applies things like delays and errors and then forwards the frames out another interface. The default naming convention which names things <interface>.<vlan> e.g. eth0.2 will not work for my purposes because the program which parses the configuration script for the networking application doesn't like the decimal in the interface name. I ran vconfig set_name_type VLAN_PLUS_VID which solves the decimal in the interface name problem, however, I can then no longer assign the same vlan id to multiple interfaces because they have the same name. I know how to change physical interface names using udev rules, but because the vlan's will have the same MAC address and they aren't physical interfaces I can't use those rules to rename the interfaces. Is there a way to rename any interface in linux, including the virtual ones? Is there a way to specify your own naming convention for config set_name_type option without having to recompile the source of vconfig?

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  • Slow network interaction between 2 kvm host machines

    - by VirtualNoob
    We have 2 physical machines, Host1 is a CentOS 6.4 kvm host and hosts ~7 kvm VMs all running Ubuntu 12.04 - all of this runs perfectly. Recently we've added a 2nd host system, host2, again a CentOS 6.4 kvm host with a view to running another couple of VMs and providing some failover against host1 should it be required. Both physical machines reside in the same cabinet in our DC, and are on the same subnet - let's say host1: 1.1.1.64 and host2: 1.1.1.81. Both have their gateway set to the DC gateway of 1.1.1.254 with no hardware firewall in between. On each machine, I have 4 NICs that are bonded together to form a single interface, which is then bridged to allow the VMs to access the network. All of the VMs are online, and all of them can successfully ssh into the hosts without any delay. Both systems can access the internet fine, and I can ssh into both systems from home without any issues. However, there is a real delay when attempting to ssh from host1 to host2 (or vice versa) and this obviously means that any action required on host2, that is controlled by host1 either takes forever or results in failure due to timeout. In the interest of keeping this post short, I've put my ifcfg files into a pastie: http://pastie.org/8081648 I've tried both adding a firewall rule in each machine for the other, and also disabling the firewall entirely, so that can't be the issue. I've tried troubleshooting this myself but can't seem to get to the bottom of it. Any help or advice would be appreciated. Thanks in advance.

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  • Windows 7 laptop with two active network connections will not perform DNS AAAA lookup under certain conditions

    - by Jeff Loughridge
    My laptop has two network interfaces. The Ethernet interface connects directly to my provider's edge router. It obtains an IPv6 address via SLAAC. I manually set an IPv6 DNS server. The wireless interface connects to a CPE router that doesn't understand IPv6. If the wireless interface is disabled, I can reach the IPv6 Internet with no problems using the Ethernet interface. I run into problems when both interfaces are enabled and the wireless interface get its IPv4 DNS server via DHCP. Let's look at two scenarios. Wireless interface obtains IPv4 DNS server via DHCP - The CPE router (192.168.0.1) sends its address as the DNS server. In this scenario, Windows 7 will not perform AAAA lookups. The browser uses IPv4 transit to reach dual stack web sites. I can't reach IPv6-only web sites using domain names. I can reach IPv6-enabled web sites using IPv6 literals instead of the domain name. Wireless interface is manually configured with OpenDNS DNS server - Windows 7 performs AAAA lookups using IPv6 transit (via the Ethernet). Everything works fine. My dual homed set-up is definitely not standard. Still, the behavior is very strange to me. A valid IPv6 interface exists in my Ethernet interface. Why won't Windows attempt AAAA lookups in scenario #1? I've included the output of ipconfig /all and netstat -rn. C:\Program Files\Console>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : jake Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : res.openband.net Wireless LAN adapter Wireless Network Connection 2: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft Virtual WiFi Miniport Adapter Physical Address. . . . . . . . . : C0-CB-38-06-54-F9 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Wireless LAN adapter Wireless Network Connection: Connection-specific DNS Suffix . : res.openband.net Description . . . . . . . . . . . : DW1520 Wireless-N WLAN Half-Mini Card Physical Address. . . . . . . . . : C0-CB-38-06-54-F9 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::fc39:9293:7d01:4a75%13(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.0.105(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Wednesday, July 11, 2012 7:35:21 AM Lease Expires . . . . . . . . . . : Thursday, July 12, 2012 9:49:46 AM Default Gateway . . . . . . . . . : 192.168.0.1 DHCP Server . . . . . . . . . . . : 192.168.0.1 DHCPv6 IAID . . . . . . . . . . . : 364956472 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C DNS Servers . . . . . . . . . . . : 208.67.222.222 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : res.openband.net Description . . . . . . . . . . . : Intel(R) 82577LM Gigabit Network Connection Physical Address. . . . . . . . . : 5C-26-0A-03-23-5C DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IPv6 Address. . . . . . . . . . . : 2607:2600:1:850:c0e9:211a:fd05:4e0b(Preferred) Temporary IPv6 Address. . . . . . : 2607:2600:1:850:3d29:1839:62db:c4c1(Preferred) Link-local IPv6 Address . . . . . : fe80::c0e9:211a:fd05:4e0b%12(Preferred) IPv4 Address. . . . . . . . . . . : 10.52.2.51(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.254.0 Lease Obtained. . . . . . . . . . : Monday, July 09, 2012 8:55:07 AM Lease Expires . . . . . . . . . . : Thursday, July 12, 2012 7:30:05 AM Default Gateway . . . . . . . . . : fe80::214:6aff:fe51:7f3f%12 10.52.2.1 DHCP Server . . . . . . . . . . . : 216.40.77.244 DNS Servers . . . . . . . . . . . : 2620:0:ccc::2 2620:0:ccd::2 216.40.77.126 216.40.77.244 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter VMware Network Adapter VMnet1: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet1 Physical Address. . . . . . . . . : 00-50-56-C0-00-01 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::4c61:495b:229e:281e%14(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.40.1(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : DHCPv6 IAID . . . . . . . . . . . : 469782614 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1 fec0:0:0:ffff::2%1 fec0:0:0:ffff::3%1 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter VMware Network Adapter VMnet8: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet8 Physical Address. . . . . . . . . : 00-50-56-C0-00-08 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::f996:61eb:8c00:45e6%15(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.17.1(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : DHCPv6 IAID . . . . . . . . . . . : 486559830 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1 fec0:0:0:ffff::2%1 fec0:0:0:ffff::3%1 NetBIOS over Tcpip. . . . . . . . : Enabled C:\Program Files\Console>netstat -rn =========================================================================== Interface List 17...c0 cb 38 06 54 f9 ......Microsoft Virtual WiFi Miniport Adapter 13...c0 cb 38 06 54 f9 ......DW1520 Wireless-N WLAN Half-Mini Card 12...5c 26 0a 03 23 5c ......Intel(R) 82577LM Gigabit Network Connection 11...5c ac 4c f8 b8 55 ......Bluetooth Device (Personal Area Network) 14...00 50 56 c0 00 01 ......VMware Virtual Ethernet Adapter for VMnet1 15...00 50 56 c0 00 08 ......VMware Virtual Ethernet Adapter for VMnet8 1...........................Software Loopback Interface 1 =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 10.52.2.1 10.52.2.51 10 0.0.0.0 0.0.0.0 192.168.0.1 192.168.0.105 100 10.52.2.0 255.255.254.0 On-link 10.52.2.51 261 10.52.2.51 255.255.255.255 On-link 10.52.2.51 261 10.52.3.255 255.255.255.255 On-link 10.52.2.51 261 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 192.168.0.0 255.255.255.0 On-link 192.168.0.105 306 192.168.0.105 255.255.255.255 On-link 192.168.0.105 306 192.168.0.255 255.255.255.255 On-link 192.168.0.105 306 192.168.17.0 255.255.255.0 On-link 192.168.17.1 276 192.168.17.1 255.255.255.255 On-link 192.168.17.1 276 192.168.17.255 255.255.255.255 On-link 192.168.17.1 276 192.168.40.0 255.255.255.0 On-link 192.168.40.1 276 192.168.40.1 255.255.255.255 On-link 192.168.40.1 276 192.168.40.255 255.255.255.255 On-link 192.168.40.1 276 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 10.52.2.51 261 224.0.0.0 240.0.0.0 On-link 192.168.0.105 306 224.0.0.0 240.0.0.0 On-link 192.168.40.1 276 224.0.0.0 240.0.0.0 On-link 192.168.17.1 276 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 10.52.2.51 261 255.255.255.255 255.255.255.255 On-link 192.168.0.105 306 255.255.255.255 255.255.255.255 On-link 192.168.40.1 276 255.255.255.255 255.255.255.255 On-link 192.168.17.1 276 =========================================================================== Persistent Routes: None IPv6 Route Table =========================================================================== Active Routes: If Metric Network Destination Gateway 12 261 ::/0 fe80::214:6aff:fe51:7f3f 1 306 ::1/128 On-link 12 13 2607:2600:1:850::/64 On-link 12 261 2607:2600:1:850:3d29:1839:62db:c4c1/128 On-link 12 261 2607:2600:1:850:c0e9:211a:fd05:4e0b/128 On-link 12 261 fe80::/64 On-link 13 281 fe80::/64 On-link 14 276 fe80::/64 On-link 15 276 fe80::/64 On-link 14 276 fe80::4c61:495b:229e:281e/128 On-link 12 261 fe80::c0e9:211a:fd05:4e0b/128 On-link 15 276 fe80::f996:61eb:8c00:45e6/128 On-link 13 281 fe80::fc39:9293:7d01:4a75/128 On-link 1 306 ff00::/8 On-link 12 261 ff00::/8 On-link 13 281 ff00::/8 On-link 14 276 ff00::/8 On-link 15 276 ff00::/8 On-link =========================================================================== Persistent Routes: None

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  • CLSF & CLK 2013 Trip Report by Jeff Liu

    - by jamesmorris
    This is a contributed post from Jeff Liu, lead XFS developer for the Oracle mainline Linux kernel team. Recently, I attended both the China Linux Storage and Filesystem workshop (CLSF), and the China Linux Kernel conference (CLK), which were held in Shanghai. Here are the highlights for both events. CLSF - 17th October XFS update (led by Jeff Liu) XFS keeps rapid progress with a lot of changes, especially focused on the infrastructure/performance improvements as well as  new feature development.  This can be reflected with a sample statistics among XFS/Ext4+JBD2/Btrfs via: # git diff --stat --minimal -C -M v3.7..v3.12-rc4 -- fs/xfs|fs/ext4+fs/jbd2|fs/btrfs XFS: 141 files changed, 27598 insertions(+), 19113 deletions(-) Ext4+JBD2: 39 files changed, 10487 insertions(+), 5454 deletions(-) Btrfs: 70 files changed, 19875 insertions(+), 8130 deletions(-) What made up those changes in XFS? Self-describing metadata(CRC32c). This is a new feature and it contributed about 70% code changes, it can be enabled via `mkfs.xfs -m crc=1 /dev/xxx` for v5 superblock. Transaction log space reservation improvements. With this change, we can calculate the log space reservation at mount time rather than runtime to reduce the the CPU overhead. User namespace support. So both XFS and USERNS can be enabled on kernel configuration begin from Linux 3.10. Thanks Dwight Engen's efforts for this thing. Split project/group quota inodes. Originally, project quota can not be enabled with group quota at the same time because they were share the same quota file inode, now it works but only for v5 super block. i.e, CRC enabled. CONFIG_XFS_WARN, an new lightweight runtime debugger which can be deployed in production environment. Readahead log object recovery, this change can speed up the log replay progress significantly. Speculative preallocation inode tracking, clearing and throttling. The main purpose is to deal with inodes with post-EOF space due to speculative preallocation, support improved quota management to free up a significant amount of unwritten space when at or near EDQUOT. It support backgroup scanning which occurs on a longish interval(5 mins by default, tunable), and on-demand scanning/trimming via ioctl(2). Bitter arguments ensued from this session, especially for the comparison between Ext4 and Btrfs in different areas, I have to spent a whole morning of the 1st day answering those questions. We basically agreed on XFS is the best choice in Linux nowadays because: Stable, XFS has a good record in stability in the past 10 years. Fengguang Wu who lead the 0-day kernel test project also said that he has observed less error than other filesystems in the past 1+ years, I own it to the XFS upstream code reviewer, they always performing serious code review as well as testing. Good performance for large/small files, XFS does not works very well for small files has already been an old story for years. Best choice (maybe) for distributed PB filesystems. e.g, Ceph recommends delopy OSD daemon on XFS because Ext4 has limited xattr size. Best choice for large storage (>16TB). Ext4 does not support a single file more than around 15.95TB. Scalability, any objection to XFS is best in this point? :) XFS is better to deal with transaction concurrency than Ext4, why? The maximum size of the log in XFS is 2038MB compare to 128MB in Ext4. Misc. Ext4 is widely used and it has been proved fast/stable in various loads and scenarios, XFS just need more customers, and Btrfs is still on the road to be a manhood. Ceph Introduction (Led by Li Wang) This a hot topic.  Li gave us a nice introduction about the design as well as their current works. Actually, Ceph client has been included in Linux kernel since 2.6.34 and supported by Openstack since Folsom but it seems that it has not yet been widely deployment in production environment. Their major work is focus on the inline data support to separate the metadata and data storage, reduce the file access time, i.e, a file access need communication twice, fetch the metadata from MDS and then get data from OSD, and also, the small file access is limited by the network latency. The solution is, for the small files they would like to store the data at metadata so that when accessing a small file, the metadata server can push both metadata and data to the client at the same time. In this way, they can reduce the overhead of calculating the data offset and save the communication to OSD. For this feature, they have only run some small scale testing but really saw noticeable improvements. Test environment: Intel 2 CPU 12 Core, 64GB RAM, Ubuntu 12.04, Ceph 0.56.6 with 200GB SATA disk, 15 OSD, 1 MDS, 1 MON. The sequence read performance for 1K size files improved about 50%. I have asked Li and Zheng Yan (the core developer of Ceph, who also worked on Btrfs) whether Ceph is really stable and can be deployed at production environment for large scale PB level storage, but they can not give a positive answer, looks Ceph even does not spread over Dreamhost (subject to confirmation). From Li, they only deployed Ceph for a small scale storage(32 nodes) although they'd like to try 6000 nodes in the future. Improve Linux swap for Flash storage (led by Shaohua Li) Because of high density, low power and low price, flash storage (SSD) is a good candidate to partially replace DRAM. A quick answer for this is using SSD as swap. But Linux swap is designed for slow hard disk storage, so there are a lot of challenges to efficiently use SSD for swap. SWAPOUT swap_map scan swap_map is the in-memory data structure to track swap disk usage, but it is a slow linear scan. It will become a bottleneck while finding many adjacent pages in the use of SSD. Shaohua Li have changed it to a cluster(128K) list, resulting in O(1) algorithm. However, this apporoach needs restrictive cluster alignment and only enabled for SSD. IO pattern In most cases, the swap io is in interleaved pattern because of mutiple reclaimers or a free cluster is shared by all reclaimers. Even though block layer can merge interleaved IO to some extent, but we cannot count on it completely. Hence the per-cpu cluster is added base on the previous change, it can help reclaimer do sequential IO and the block layer will be easier to merge IO. TLB flush: If we're reclaiming one active page, we should first move the page from active lru list to inactive lru list, and then reclaim the page from inactive lru to swap it out. During the process, we need to clear PTE twice: first is 'A'(ACCESS) bit, second is 'P'(PRESENT) bit. Processors need to send lots of ipi which make the TLB flush really expensive. Some works have been done to improve this, including rework smp_call_functiom_many() or remove the first TLB flush in x86, but there still have some arguments here and only parts of works have been pushed to mainline. SWAPIN: Page fault does iodepth=1 sync io, but it's a little waste if only issue a page size's IO. The obvious solution is doing swap readahead. But the current in-kernel swap readahead is arbitary(always 8 pages), and it always doesn't perform well for both random and sequential access workload. Shaohua introduced a new flag for madvise(MADV_WILLNEED) to do swap prefetch, so the changes happen in userspace API and leave the in-kernel readahead unchanged(but I think some improvement can also be done here). SWAP discard As we know, discard is important for SSD write throughout, but the current swap discard implementation is synchronous. He changed it to async discard which allow discard and write run in the same time. Meanwhile, the unit of discard is also optimized to cluster. Misc: lock contention For many concurrent swapout and swapin , the lock contention such as anon_vma or swap_lock is high, so he changed the swap_lock to a per-swap lock. But there still have some lock contention in very high speed SSD because of swapcache address_space lock. Zproject (led by Bob Liu) Bob gave us a very nice introduction about the current memory compression status. Now there are 3 projects(zswap/zram/zcache) which all aim at smooth swap IO storm and promote performance, but they all have their own pros and cons. ZSWAP It is implemented based on frontswap API and it uses a dynamic allocater named Zbud to allocate free pages. Zbud means pairs of zpages are "buddied" and it can only store at most two compressed pages in one page frame, so the max compress ratio is 50%. Each page frame is lru-linked and can do shink in memory pressure. If the compressed memory pool reach its limitation, shink or reclaim happens. It decompress the page frame into two new allocated pages and then write them to real swap device, but it can fail when allocating the two pages. ZRAM Acts as a compressed ramdisk and used as swap device, and it use zsmalloc as its allocator which has high density but may have fragmentation issues. Besides, page reclaim is hard since it will need more pages to uncompress and free just one page. ZRAM is preferred by embedded system which may not have any real swap device. Now both ZRAM and ZSWAP are in driver/staging tree, and in the mm community there are some disscussions of merging ZRAM into ZSWAP or viceversa, but no agreement yet. ZCACHE Handles file page compression but it is removed out of staging recently. From industry (led by Tang Jie, LSI) An LSI engineer introduced several new produces to us. The first is raid5/6 cards that it use full stripe writes to improve performance. The 2nd one he introduced is SandForce flash controller, who can understand data file types (data entropy) to reduce write amplification (WA) for nearly all writes. It's called DuraWrite and typical WA is 0.5. What's more, if enable its Dynamic Logical Capacity function module, the controller can do data compression which is transparent to upper layer. LSI testing shows that with this virtual capacity enables 1x TB drive can support up to 2x TB capacity, but the application must monitor free flash space to maintain optimal performance and to guard against free flash space exhaustion. He said the most useful application is for datebase. Another thing I think it's worth to mention is that a NV-DRAM memory in NMR/Raptor which is directly exposed to host system. Applications can directly access the NV-DRAM via a memory address - using standard system call mmap(). He said that it is very useful for database logging now. This kind of NVM produces are beginning to appear in recent years, and it is said that Samsung is building a research center in China for related produces. IMHO, NVM will bring an effect to current os layer especially on file system, e.g. its journaling may need to redesign to fully utilize these nonvolatile memory. OCFS2 (led by Canquan Shen) Without a doubt, HuaWei is the biggest contributor to OCFS2 in the past two years. They have posted 46 upstream patches and 39 patches have been merged. Their current project is based on 32/64 nodes cluster, but they also tried 128 nodes at the experimental stage. The major work they are working is to support ATS (atomic test and set), it can be works with DLM at the same time. Looks this idea is inspired by the vmware VMFS locking, i.e, http://blogs.vmware.com/vsphere/2012/05/vmfs-locking-uncovered.html CLK - 18th October 2013 Improving Linux Development with Better Tools (Andi Kleen) This talk focused on how to find/solve bugs along with the Linux complexity growing. Generally, we can do this with the following kind of tools: Static code checkers tools. e.g, sparse, smatch, coccinelle, clang checker, checkpatch, gcc -W/LTO, stanse. This can help check a lot of things, simple mistakes, complex problems, but the challenges are: some are very slow, false positives, may need a concentrated effort to get false positives down. Especially, no static checker I found can follow indirect calls (“OO in C”, common in kernel): struct foo_ops { int (*do_foo)(struct foo *obj); } foo->do_foo(foo); Dynamic runtime checkers, e.g, thread checkers, kmemcheck, lockdep. Ideally all kernel code would come with a test suite, then someone could run all the dynamic checkers. Fuzzers/test suites. e.g, Trinity is a great tool, it finds many bugs, but needs manual model for each syscall. Modern fuzzers around using automatic feedback, but notfor kernel yet: http://taviso.decsystem.org/making_software_dumber.pdf Debuggers/Tracers to understand code, e.g, ftrace, can dump on events/oops/custom triggers, but still too much overhead in many cases to run always during debug. Tools to read/understand source, e.g, grep/cscope work great for many cases, but do not understand indirect pointers (OO in C model used in kernel), give us all “do_foo” instances: struct foo_ops { int (*do_foo)(struct foo *obj); } = { .do_foo = my_foo }; foo>do_foo(foo); That would be great to have a cscope like tool that understands this based on types/initializers XFS: The High Performance Enterprise File System (Jeff Liu) [slides] I gave a talk for introducing the disk layout, unique features, as well as the recent changes.   The slides include some charts to reflect the performances between XFS/Btrfs/Ext4 for small files. About a dozen users raised their hands when I asking who has experienced with XFS. I remembered that when I asked the same question in LinuxCon/Japan, only 3 people raised their hands, but they are Chris Mason, Ric Wheeler, and another attendee. The attendee questions were mainly focused on stability, and comparison with other file systems. Linux Containers (Feng Gao) The speaker introduced us that the purpose for those kind of namespaces, include mount/UTS/IPC/Network/Pid/User, as well as the system API/ABI. For the userspace tools, He mainly focus on the Libvirt LXC rather than us(LXC). Libvirt LXC is another userspace container management tool, implemented as one type of libvirt driver, it can manage containers, create namespace, create private filesystem layout for container, Create devices for container and setup resources controller via cgroup. In this talk, Feng also mentioned another two possible new namespaces in the future, the 1st is the audit, but not sure if it should be assigned to user namespace or not. Another is about syslog, but the question is do we really need it? In-memory Compression (Bob Liu) Same as CLSF, a nice introduction that I have already mentioned above. Misc There were some other talks related to ACPI based memory hotplug, smart wake-affinity in scheduler etc., but my head is not big enough to record all those things. -- Jeff Liu

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