Search Results

Search found 596 results on 24 pages for 'gigabit'.

Page 19/24 | < Previous Page | 15 16 17 18 19 20 21 22 23 24  | Next Page >

  • Network connection keeps dropping - bad hardware?

    - by Bill Sambrone
    Hello all, I've into a bit of a wall with a client of mine. In an office of 20 people, he is the only one who experiences broken connections to his mapped network drives. I have everyone set up with about 6 mapped drives, all pointing to the same server (no DFS), and everyone else can access them lightning fast. The environment consists of a mix of Windows 7 and XP machines, all 32-bit. The server holding the data everyone is mapping to is running on Server 2008 R2, and is a domain controller. We recently swapped out their old 10/100 switch for a shiny new Dell PowerConnect gigabit switch. We have also replaced an old dying Sonicwall with a shiny new one. Everything is running on an ESX host except for the DC, where everyone is getting data from. In my client's office, we have done the following: Swapped out his computer (Win7 and XP box) Swapped out the desktop switch in his office Removed the desktop switch in his office Changed out the network cable going to the wall Ran 'net config server /autodisconnect:-1' on the server Disabled remote differential compression on his current Win7 box When we swapped out his network cable, everything seemed fine for about 4 days. Normally I would get a phone call a couple times per day letting me know that Outlook has crashed (there is a 9GB PST living on the server he is always connected to), or that his software he is running from his L drive has crashed. I almost thought I had this solved, but after we rebooted the DC the other night he all of a sudden couldn't stay connected to his mapped network drives for more than 10 minutes. When I ran 'net use' from the command prompt, it listed all the network drives where were randomly in a state of 'OK', 'Disconnected', or 'Reconnecting'. What else should I try? Maybe there is bad wiring in the wall, patch panel, or a bad port in the new switch I have in the server room?

    Read the article

  • External Storage for 2TB of backups and 4TB of data RAID level? HW vs Software?

    - by Jerry Mayers
    I have a Mac Mini set up as a media center/file server. Currently I just have a hodgepodge mess of external drives for storage. I'm maxed out, and I have some new laptops on the way with much larger drives and I need to work out a good storage solution for backing them up, as well as storing media on the server. I need around 2 TB of storage for the time machine backups from my various systems and around 2 TB more for media. I would like to build this to handle around 6 TB total so I have some growing room. Since I'm using a Mac Mini as the server I need to use external enclosure(s) that support USB 2 or Firewire 800 (preferred) or gigabit Ethernet. Performance of the system isn't a huge concern since the majority of the access from other computers is done over 802.11N. I plan on using 2TB drives, for the final version, but initially I'll try and use my existing 2 (1TB) drives + some new 2TB drives, and swap the 1TB ones out as I fill up. As to the actual questions: Should I use hardware RAID in some enclosure? Because if the enclosure dies I have to find an identical one to get to my data right? Wouldn't a software RAID be better as I can use any method of connecting the drives to the system? Remember OS X server is my OS. What if I had to reinstall OS X, can I restore the software RAID easily? What RAID version should I use? For the 2TB used for the time machine disk I don't see why I need RAID here, just a single 2TB drive since its already the backup, but for the remaining 4TB it would be the only copy of the data so I should build some redundancy. I had a RAID 5 setup using a cheep RAID PCI card years ago running RAID 5 in a 2 TB array and when a drive died it wanted 48 hours to rebuild. Is this crazy slow for a setup of this size or is this to be expected? Any suggestions as to drive enclosures?

    Read the article

  • Find slow network nodes between two data centers

    - by 2called-chaos
    I've got a problem with syncing big amount of data between two data centers. Both machines have got a gigabit connection and are not fully occupied but the fastest that I am able to get is something between 6 and 10 Mbit = not acceptable! Yesterday I made some traceroute which indicates huge load on a LEVEL3 router but the problem exists for weeks now and the high response time is gone (20ms instead of 300ms). How can I trace this to find the actual slow node? Thought about a traceroute with bigger packages but will this work? In addition this problem might not be related to one of our servers as there are much higher transmission rates to other servers or clients. Actually office = server is faster than server <= server! Any idea is appreciated ;) Update We actually use rsync over ssh to copy the files. As encryption tends to have more bottlenecks I tried a HTTP request but unfortunately it is just as slow. We have a SLA with one of the data centers. They said they already tried to change the routing because they say this is related to a cheap network where the traffic gets routed through. It is true that it will route through a "cheapnet" but only the other way around. Our direction goes through LEVEL3 and the other way goes through lambdanet (which they said is not a good network). If I got it right (I'm a network intermediate) they simulated a longer path to force routing through LEVEL3 and they announce LEVEL3 in the AS path. I basically want to know if they're right or they're just trying to abdicate their responsibility. The thing is that the problem exists in both directions (while different routes), so I think it is in the responsibility of our hoster. And honestly, I don't believe that there is a DC2DC connection which only can handle 600kb/s - 1,5 MB/s for weeks! The question is how to detect WHERE this bottleneck is

    Read the article

  • How to configure a large mtu (linux)

    - by Somejan
    I have a gigabit ethernet connection from my laptop to my router, and a working ipv6 connection to the internet. I can receive very large packets from sites on the internet, with sizes up to at least 10000 bytes (according to wireshark). (edit: turns out to be linux's 'generic receive offload') However, when trying to send anything, my local computer fragments at just below 1500 bytes for ipv6. (On ipv4, I can send tcp packets to the internet of at least 1514 bytes, I can ping with packets up to the configured mtu of 6128 but they are blackholed.) I'm on ubuntu 12.04. I have configured an mtu for my eth0 of 6128 (the maximum it accepts), both using ip link set dev eth0 mtu 6128 and in the NetworkManager applet gui, and restarted the connection. ip link show eth0 shows the 6128 mtu is indeed set. ip -6 route shows that none of the paths the kernel knows about have an mtu set. I can ping over ipv4 with packets up to 6128 bytes (though I don't get responses), but when I do ping6 myrouter -c3 -s1500 -Mdo I get error replies from my own computer saying that the packets are too large and the mtu is 1480. I have confirmed with Wireshark that nothing is put on the wire, and the replies are indeed generated by my own computer. So, how do I get my computer to use the larger mtu?

    Read the article

  • When should NTPd broadcast/broadcastclient be used instead of client/server or peer modes?

    - by Luke404
    The NTP deamon if often used in its simplest mode, which is client/server: you specify one or more server directives in your ntp.conf and your clients will use those servers. In addition to that, when you run your own NTP servers, it is good practice to peer them together, so if one of them looses connectivity to its upstream servers, it will get time from its peers. But NTPd can also work with broadcast and/or multicast distribution of time data, with the documentation stating: broadcast and multicast modes are intended for configurations involving one or a few servers and a possibly very large client population The documentation also says elsewhere: It is possible and frequently useful to configure a host as both broadcast client and broadcast server. A number of hosts configured this way and sharing a common broadcast address will automatically organize themselves in an optimum configuration based on stratum and synchronization distance. I can see one obvious administrative benefit: you don't have to manually specify and update your list of NTP servers in the clients ntp.conf, so to me it looks tempting to use broadcast mode even for a small client population (say 5+ clients with 3~4 servers). I expect network traffic to be a little higher with broadcasts instead of client/server associations, but given the usual gigabit ethernet LAN the impact should be negligible unless you have a very very large number of hosts in the same broadcast domain. At the end of the day, when should broadcast mode be used or avoided? Are there pros and cons I haven't seen?

    Read the article

  • RDP Connection to Windows 7 stays really slow

    - by Pavlo
    I have an Issue with connecting to Windows 7 via RDP. I can open an RDP Session, but regardless of any settings, the responce times are really long. This in particulary is the case when opening a web page in a browser. I've tried IE, Firefox and Google Chrome. I also use RDP connection to a Windows 2008 Server from the same client machine, and the speed is very normal with all features turned on. We have Gigabit Ethernet here. So I think it can not be the client's fault. What concerns Windows 7 Machine, I've tried shutting all the sraphic features off and turning the color levels to 256 colors. Result - the same. If I work locally on the machine - I can not see any lags. What else have I tried: Using old RDP 5 Client from Microsoft Setting network autotuninglevel as seen here Do You have some ideas? Thanks in advance! Update the problem seems to be with rendering window contents. All the window borders and pannes are rendered pretty quickly, but the content shows up very slowly. Also mouse movements are recognised by the Win 7 box only after some period. Are there some hidden settings in the RDP, where one could turn some advanced features off or turn some caching on? I use Bitmap Caching, but this apparently doesn't help.

    Read the article

  • Photoshop CS5 performance over network drive (cifs)

    - by grub
    Hello Everyone I did install a QNAP NAS TS410 for a customer (professional photographer) with 3 Hitachi Deskstar 7200rpm 2TB disk configured as RAID5. The NAS and the workstations are connected over a Gigabit network. He and his co-worker are accessing the photos (about 1TB of photos) over a mapped network drive from their windows machines (Windows XP - 32bit and Windows 7 Ultimate - 32bit). Both are using Photoshop CS5 to edit the photos. The problem is that to save a edited photo takes a really long time, it takes about 3 times as long to save a photo as to open it. After some tests I can exclude the network, the NAS and the windows machines as source of the issue. I think the problem is the Photoshop software and its handling of the network drives. Officially network drives are not supported by Adobe. I do not have any experience with the Adobe products, especially with Adobe Photoshop CS5. What are your recommendation to solve the performance issue? Should my customer copy the photos to the local drive, edit them and upload them again to the network drive or is Adobe Drive or Adobe Version Cue the answer? One requirement is that the photos need to be accessible / editable from both computers even when one of them is offline. Adobe Version Cue needs a dedicated service running to be usable, so this solution is not possible as far as I understand the Cue software. Thank you for your input to this issue and have a nice day :-) Greetings grub

    Read the article

  • PCs on domain can not resolve external IP addresses using the DC's DNS Server

    - by Ben
    I currently have a domain controller which handles all DHCP and DNS. The DHCP works just fine and the domain controller itself can use the internet with no issues. However, PCs that are part of the domain are not able to use external websites, only internal. Does anyone have any way I can solve this issue? Thank you Server: Windows Server 2008 R2 PC: Win7 Enterprise x64 Edit: (domain controller) C:\Users\bcollyer>nslookup google.com Server: localhost Address: 127.0.0.1 Non-authoritative answer: Name: google.com Addresses: 2a00:1450:4009:809::100e 173.194.41.166 173.194.41.165 173.194.41.169 173.194.41.162 173.194.41.161 173.194.41.160 173.194.41.168 173.194.41.167 173.194.41.164 173.194.41.163 173.194.41.174 Edit 2: C:\Users\bcollyernetstat -rn Interface List 12...30 85 a9 f7 8a 21 ......Atheros AR8161/8165 PCI-E Gigabit Ethernet Control ler (NDIS 6.20) 1...........................Software Loopback Interface 1 13...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter 11...00 00 00 00 00 00 00 e0 Microsoft Teredo Tunneling Adapter IPv4 Route Table Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 172.16.0.67 172.16.0.202 20 127.0.0.0 255.0.0.0 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 127.0.0.1 306 172.16.0.0 255.255.0.0 On-link 172.16.0.202 276 172.16.0.202 255.255.255.255 On-link 172.16.0.202 276 172.16.255.255 255.255.255.255 On-link 172.16.0.202 276 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 172.16.0.202 276 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 172.16.0.202 276 Persistent Routes: None IPv6 Route Table Active Routes: If Metric Network Destination Gateway 1 306 ::1/128 On-link 1 306 ff00::/8 On-link Persistent Routes: None BTW I have no javascript on the server so can't reply to individual answers... Sorry!

    Read the article

  • Offloading backups to secondary network

    - by user1467163
    I'm trying to solve a problem- Currently, we are constantly backing up and have no budget for additional servers. Our production network is still a 10/100 and handles voip, SQL plus our backup traffic, and I'd like to offload the backup traffic onto a secondary network- all of our servers have secondary NIC's that are not in use, and all support gigabit (Our switching hardware does not- a topic for another day). I'd like to move my backups off the production network, but I am having a hard time getting the computers to communicate. I am using a Netgear GS724T switch for the backup network- Chosen for cost and because I have used them extensively on networks saturated with ghosting traffic, so I know it's up to the task. I have defined a VLAN, with ports that are not members of any other VLAN. All traffic is untagged on the VLAN. I have set the servers with 192.168.1.10 and 192.168.1.11 addresses, 255.255.255.0 netmask and I have tried a blank GW, using the local IP of the server 192.168.1.whatever address, and I have tried using the switch's production-side IP as the GW. The machines cannot find each other. DNS addresses are blank because I am going purely by IP for now... Any ideas how to get these machines to talk? they are Windows machines, running Server 2008R2 and 2003R2. Thanks!

    Read the article

  • "Error 53" with local LAN machines after VPN session on server

    - by tim11g
    I have a Windows 2000 server with a Windows 7 client that occasionally gets "error 53" when accessing the server by name (net view \\server). It still works by IP address (net view \\192.168.0.1). The server's primary IP address (as shown in "routing and remote access" as "Gigabit Ethernet" is 192.168.0.1. There is also a secondary IP address shown as "Internal" which is 192.168.0.50 The server also supports VPN. When a VPN user connects, it gets an address in the range of 192.168.0.51 to .59. Normally (when there is no error), when the local LAN client runs "ping server", it resolves to 192.168.0.1. When the Error 53 problem happens, "ping server" resolves to 192.168.0.50. This problem seems to be related to when a user connects or has recently connected to the server VPN. Is there some connection between the VPN services on the server and the DNS services on the server that could cause a local LAN client to become confused about which IP address to use for the server? Or is there a misconfiguration in the VPN or DNS?

    Read the article

  • What Media Extender / Centre Set up should I use?

    - by Bryn Hird
    I have installed cat6 throughout the house which I use for telephony and network. In my cellar I have a NAS Server, gigabit switch and I want to install a Media Centre to stream my video's, music, photo's and live TV (coax from the aerial to the cellar) over the cat6. Yeah I know I can get stuff on the internet but shared experience of watching TV as a family as it happens is a big plus for live TV. I'm aiming for 1080p. I want different users to be able to watch different channels. Max users = 4. I've played a little with Windows Media Centre, works fine with live TV. Likewise I have XBMC up and running with live TV. The issue I have is what do I put near the TV. I'd like a consistent user interface (grandma and the the other technophobes in the house are continually pestering me on how to use different TVs, change channel, inputs etc.) so a key part of this for me is to make the user experience the same and simple i.e. no keyboards / PCs hanging around the TV. I've just bought a Linksys DMA 2200 to test the Windows Media Centre, but obviously off eBay as they're a dying breed. And with Windows Media Centre removed from Microsoft plans such devices will get rarer. And as for 1080p, think I can forget it with that set up. I have tested XBOX 360, also works but ditto on Microsoft plans for WMC. I was thinking of a WD Live TV to test the XMBC setup. Now to the question. Any advice on Media Centre / Extender setups that will do the job as above and have some degree of futureproofing (building my own with my Raspberry PI is a last resort). I'd like to understand the standards involved in the futureproofing if anyone knows (DNLA, RVU etc.).

    Read the article

  • High-performance Academic Server [closed]

    - by PHPsmith
    Suppose I want to build a server for the university's academic interests. The server is dedicated only to a site, where users (students and lecturers) just view and fill the academic data. But at a time (e.g. once a semester), about 12,000 students will access the site simultaneously. Due to limitation of resources, I have to build the server using free software (except for the operating system Windows 7, the university has been prepared). The hardware is also limited to the usual 4-core computers (eg, Ivy Bridge Intel Core i7-3770) with approximately 16GB of memory (DDR3 1600 MHz), equipped with an RJ-45 port (Intel 82 579 Gigabit Ethernet). With all these limitations, I have to choose the software (web server, database, etc) are appropriate for this purpose is achieved. I decided to create a site in PHP. Please help me by answering the following questions based on your expertise. (my prime candidate software to consider after googling) Web server which is faster & stable & secure, when implemented and optimized for PHP? And why? (nginx) PHP accelerator which is faster & stable & compatible with the selected web server? And why? (APC with Zend Optimizer+) Database which is faster & stable & secure, when implemented and optimized for selected web server and selected PHP accelerator? (MySQL) Are there any errors that have been or will be happening from my condition is? If there is, please enlighten me? Is there anything else I need to know in order to achieve this goal? If there is, please enlighten me? I understand that the performance also depends on the implementation of source-code program, so I assume it will create a site with the best efficiency (e.g. using AJAX).

    Read the article

  • What differences are there between "home" switches and "professional" switches?

    - by pjreddie
    Our radio station uses a PtP wireless system to stream our radio and TV signals from our studio up a hill to our transmitter. We have been having problems with warbly sound and drop outs that come from some point in this system. An engineer that occasionally visits the station thinks it could be the switches we use on each side of the PtP wireless system to connect the PtP devices to the encoders and decoders and wants us to get two of these switches: http://www.amazon.com/Netgear-JGS516-ProSafe-16-Port-Ethernet/dp/B0002CWPOK/ref=dp_return_1 The encoder/decoder setup only streams 8Mbps total so it seems like the switches we have should not be stressed out, unless they are causing sufficient latency to degrade the performance of the encoder/decoder. At each end of the connection we only have 4 connections, is there any reason we couldn't get a cheaper, "home" quality switch like this: http://www.amazon.com/D-Link-DGS-1005G-5-Port-Gigabit-Desktop/dp/tech-data/B003X7TRWE/ref=de_a_smtd Is there a significant difference that we would notice in terms of latency between these two switches? How much does the quality of the switch actually matter in this scenario? Any help is appreciated, feel free to ask questions if anything needs clarification. Thanks

    Read the article

  • BackupExec 12 + RALUS - VERY slow backups

    - by LVDave
    We use Backup Exec 12 and the Remote Agent for Linux/Unix Servers (RALUS) to backup a large RHEL5 system. For various reasons we need to do a daily working set job. These working-set jobs run abysmally slow. The link between the target machine and the BE server is gigabit, and any other type of job runs 1-3GB/min. These working-set jobs start out at perhaps 40MB/min and over the course of the backup job slowly drops down so low that the BE job rate display in the "current jobs" goes blank.. Since we usually are only doing changed-files for one day, the job is usually small and finishes overnight and we don't worry abotu the slowness, but we had some issues with the backup server, and missed about 6 days of fairly heavy work on the Linux box, so this working-set job will be a doozy.. We have support with Symantec, and I've pestered them a lot about this, they've had me run RALUS in debug mode, sent them that log and a VXgather from the BE host and they had no fix/workaround.. To give an idea, I have the mentioned working-set job running for the last 3 1/2 hours and it's backed up just under 10MEGAbytes.... I'm posting this here to see if anybody in the "real world" has seen this/and/or has any ideas what might be causing these abysmally slow jobs, since Symantec seems to be clueless...

    Read the article

  • What does SQL Server's BACKUPIO wait type mean?

    - by solublefish
    I'm using Sql Server 2008 ("R1"), with some maintenance plans that back up my databases to a network share. Some of my backup jobs show long waits of type "BACKUPIO". Of course it seems like this is an I/O subsystem limitation, but I'm skeptical. Perfmon stats for I/O on the production (source) server are well within normal trends for that server. The destination server shows a sustained 7MB/s write rate, which seems incredibly low, even for a slow disk. The network link is gigabit ethernet and nowhere near saturated. The few docs I've turned up about BACKUPIO indicate that it's not specifically a wait on I/O, surprisingly enough. This MSFT doc says it's abnormal unless you're using a tape drive, which I'm not. But it doesn't say (or I don't understand) exactly what resource is missing. http://www.docstoc.com/docs/24580659/Performance-Tuning-in-SQL-Server-2005 And this piece says it's not related to I/O performance at all. http://www.informit.com/articles/article.aspx?p=686168&seqNum=5 "Note that BACKUPIO and IO_AUDIT_MUTEX are not related to IO performance." Anyway, does anyone know what BACKUPIO actually means and/or what I can do to diagnose or eliminate it?

    Read the article

  • Limited bandwidth and transfer rates per user.

    - by Cx03
    I searched for a while but couldn't find anything concrete, hopefully someone can help me. I'm going to be running a Debian server on a gigabit port, and want to give each user his/her fair share of internet access. The first objective is easy - transfer rates (speed) per user. From what I've looked at, IPTables/Shorewall could do the job easy. Is this easy to setup, or could one of you point me at a config? I was hoping to limit users at 300mbit or 650mbit each. The second objective gets complicated. Due to the usage of the boxes, most of the traffic will be internal network traffic that does NOT get counted to the quota. However, I still need to limit the external traffic, and if they go over, cut off access (or throttle traffic to a very low speed (10mbit?)). Let's say the user has a 3TB external traffic limit. The IF part is: If the hostname they are exchanging the traffic with DOES NOT MATCH .ovh. or .kimsufi. (company owns multiple TLDs), count to the quota. Once said quota exceeds 3TB, choke them. Where could I find a system to count that for me? It would also need to reset or be able to be manually reset on a monthly basis. Thanks ahead of time!

    Read the article

  • Diagnosing RAM issues

    - by TaylorND
    I have an old Acer Aspire T180 desktop. The specs are as follows: AMD Athlon 64 3800+ 2.4GHz 1GB DDR2 SDRAM 160GB DVD-Writer (DVD±R/±RW) Gigabit Ethernet 17" Active Matrix TFT Color LCD Windows Vista Home Basic Mini-tower AST180-UA381B According to the information in the computer's documentation the computer comes with 1 GB of RAM. It has two DDR2 SDRAM sticks. I used to have Windows Vista installed. Then I removed it and install Windows 7, and now I have since removed Windows 7 and installed Windows XP. According to Windows XP with both RAM sticks in the computer has 768 MB. Isn't this supposed to be 1 GB of RAM or 1024 MB of RAM? Is the amount of RAM installed only partly used by the Operating System? Is there's something I'm missing? If I remove either one of the RAM sticks I'm left with 448 MB of RAM. These numbers don't seem to add up. If each of the RAM sticks contains at least 448 MB of RAM shouldn't they (both being in) provide 896 MB of RAM. Even then, isn't that less than a GB of RAM? I'm not too experienced in hardware so I thought this would be the best place to ask. As a follow up question, is the RAM I have enough to run/multitask with Windows XP efficiently? I plan to do a lot of computing with the system (although not gaming), should I invest in more RAM?

    Read the article

  • Router intermittently failing

    - by nomen
    My old Asus router died a few weeks ago, so I thought I'd set up my Debian box to deal with routing my home network. I have a few complications, but I adapted my configuration from a previously working configuration, and I don't see why I am having intermittent problems. But I am having them! Every so often, my SSH connections to the router (and to the Xen virtual machines hosted by the router) just drop. I am unable to use the router's dns server. I can't ping the router. Etc. All of these things work most of the time, but break down intermittently, for a few minutes at a time. (I can provide more details, but I'm not sure what will be helpful) /etc/network/interfaces: # The loopback network interface auto lo iface lo inet loopback # Gigabit ethernet, internal network auto eth0 allow-hotplug eth0 iface eth0 inet manual # USB ethernet, internet auto eth1 allow-hotplug eth1 iface eth1 inet dhcp # Xen Bridge auto xlan0 iface xlan0 inet static bridge_ports eth0 address 10.47.94.1 netmask 255.255.255.0 As I understand it, this is sufficient to create the network interfaces, and even do some switching between Xen hosts and my eth0 interface. I installed and configured Shorewall to manage routing between the bridge and my internet-facing interface: /etc/shorewall/zones fw firewall net ipv4 lan ipv4 /etc/shorewall/interfaces net eth1 detect dhcp,tcpflags,nosmurfs,routefilter,logmartians lan xlan0 detect dhcp,tcpflags,nosmurfs,routefilter,logmartians,routeback,bridge /etc/shorewall/policy net all DROP info fw net ACCEPT info all all REJECT info /etc/shorewall/rules DNS(ACCEPT) fw net DNS(ACCEPT) lan fw Ping(ACCEPT) lan fw ... and so on, these all work, when the router is accepting traffic at all. /etc/shorewall/masq eth1 10.47.94.0/24 Also, the router is currently "working", and I checked on a problematic client: arp infrastructure infrastructure.mydomain (10.47.94.1) at 0:23:54:bb:7d:ce on en0 ifscope [ethernet] I tried it when the router was down, and I (eventually) got the same response. It took about 30 seconds to return, though.

    Read the article

  • Why just splitting an Ethernet cable does not work?

    - by Sin Jeong-hun
    I thought the Ethernet is logically one-line communication bus (for argument's sake, I am excluding hubs). All machines attached in the bus hears the same signals and the machines themselves try to avoid collisions by randomly backing off. http://computer.howstuffworks.com/ethernet6.htm If so, why splitting one Ethernet line from my home router into two and connecting two computers would not work? Why do I have to add a switch to it? *What the Internet said would not work. [4 port home router] ------[one Ethernet cable]-----[simple splitter]======[two computers] *What the Internet said I should do [4 port home router] ------[one Ethernet cable]-----[switch]======[two computers] Is this because of the signal degradation (reduced electric current)? Thank you for all the answers! The reason why I did not just use the two ports of my home router is... The 4-port gigabit router is in my room and I had put a computer in another room (also my room, though). Since wired network is far more reliable and secure, I had bought a long Ethernet cable and and connected the computer to the router. Now I was thinking about adding another computer to that room. I could buy another long Ethernet cable, but then there will be two cables between the rooms. The one line already is a minor annoyance, so I thought if I could share the one line between the two computers in that room. A switch would work, but it requires power and is a little bit pricey. That is why I wondered why it would not work to simply split the physical Ethernet cable. Apparently I do not completely understand how Ethernet and a switch work. I just have some bit of knowledge I heard in my college class.

    Read the article

  • Small maximum number of connections on a Linux router

    - by Eugene
    I have a Linux box acting as a router with no iptables or other firewall and no networking applications running on it, just pure router. I've put it in a test environment that generates many TCP connections, each having unique source and destination IP, and those connections go through this router. I'm observing that number of connections successfully created rise to approximately 500 and then no more connections can be created for several minutes, then another 100 connections can be created and there is another pause, and so on. If 10 connections for each source-destination pair are created, then maximum numbers go about 10 times up, so the problem is probably with many connections from different IPs. As traffic is simply routed, it doesn't have to do with number of file descriptors, iptables connection tracking and other things often proposed to check in similar cases. The box has plenty of free RAM and CPU, both NICs are gigabit. The kernel is 2.6.32. I've already tried increasing net.core.*mem_max, net.core.netdev_max_backlog and txqueuelen on both NICs, with completely no effect. What else should I check ? Is there some rate-limit in the kernel itself ?

    Read the article

  • Replicated filesystem and EC2 MySQL

    - by El Yobo
    I'm currently investigating migrating our infrastructure over to run on Amazon's EC2 and am trying to figure out the best way to set up a MySQL service. I'm leaning towards running our own MySQL instances, rather than going with Amazon's RDS, but am still considering the best approach for performance and cost on the instance itself. In order to have persistent data, the MySQL data needs to be on an EBS volume (with some form of striped RAID, e.g. RAID0 or RAID10) to improve persistence. However, EBS IO is limited by the network interface (gigabit, so a theoretical maximum of 128 MB/s), while the ephemeral volumes have no such problem. I did see a suggestion for running two MySQL servers on an instance, with a master running on the ephemeral disk (which we would also RAID) and a slave storing changes to an EBS volume, but this has some additional overhead and complexity (two servers). What I was imagining is using some form of replicated file system such that I could have a filesystem on top of a RAID0 of ephemeral volumes to maximise performance all changes from the above immediately replicated to another RAID1 volume backed by multiple EBS volumes to ensure no data loss The advantages of this would be best possible IO performance for the DB server; no network delay in IO decreased IO on EBS volumes (as all read IO will be done on the ephemeral volumes) so decreased cost good data security, as it's backed onto redundant EBS volumes However, I haven't seen an appropriate system to replicate all changes from one volume to the other; is there a filesystem, or any other approach, which will do this? The distributed file systems, e.g. GlusterFS, DRBD etc seem to focus on replicating disks between servers, can they be set up to do what I'm interested in here? I also haven't seen anything about other's taking this approach. Do I have a solution in need of a problem here (i.e. is performance good enough, so this whole idea is redundant)? Is there some flaw in the plan?

    Read the article

  • 3-4 old computers = general purpose cluster?

    - by TheLQ
    I have 3 old computers lying around right now running a P2 at 800 MHz(?), Intel Mobile 1.6 GHz, AMD Athlon XP 2000+ at 1.66 GHz, and (might not use this) P4 at 2.7 GHz, all with 512 MB Ram, and am considering clustering them together for fun/knowledge. They would be running an undecided version of linux, preferably ubuntu based. The issue is what I want to use it for: general computing and occasional video encoding. By general computing I mean day to day tasks. However I'm not sure if every program started by a single X session is going to exist on the same machine, defeating the purpose of such a system. Will programs be split up or exist on one machine? Second, assuming this is running 100baseT ethernet (not sure if the PCI slot itself could handle Gigabit), would the speed of having a program exist over the network be an issue? It seems that the constant asking of various things in RAM would be quite slow. And before you say "buy another computer!", that's not the point of this question. I'm asking would it be usable, not necessarily practical. And yes I know, this is going to be extreamly power consuming.

    Read the article

  • Why is my rsync so slow?

    - by iblue
    My Laptop and my workstation are both connected to a Gigabit Switch. Both are running Linux. But when I copy files with rsync, it performs badly. I get about 22 MB/s. Shouldn't I theoretically get about 125 MB/s? What is the limiting factor here? EDIT: I conducted some experiments. Write performance on the laptop The laptop has a xfs filesystem with full disk encryption. It uses aes-cbc-essiv:sha256 cipher mode with 256 bits key length. Disk write performance is 58.8 MB/s. iblue@nerdpol:~$ LANG=C dd if=/dev/zero of=test.img bs=1M count=1024 1073741824 Bytes (1.1 GB) copied, 18.2735 s, 58.8 MB/s Read performance on the workstation The files I copied are on a software RAID-5 over 5 HDDs. On top of the raid is a lvm. The volume itself is encrypted with the same cipher. The workstation has a FX-8150 cpu that has a native AES-NI instruction set which speeds up encryption. Disk read performance is 256 MB/s (cache was cold). iblue@raven:/mnt/bytemachine/imgs$ dd if=backup-1333796266.tar.bz2 of=/dev/null bs=1M 10213172008 bytes (10 GB) copied, 39.8882 s, 256 MB/s Network performance I ran iperf between the two clients. Network performance is 939 Mbit/s iblue@raven $ iperf -c 94.135.XXX ------------------------------------------------------------ Client connecting to 94.135.XXX, TCP port 5001 TCP window size: 23.2 KByte (default) ------------------------------------------------------------ [ 3] local 94.135.XXX port 59385 connected with 94.135.YYY port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 1.09 GBytes 939 Mbits/sec

    Read the article

  • Windows 7 Sharing issue on RAID 5 Array(s)

    - by K.A.I.N
    Greetings all, I'm having a very odd error with a windows 7 ultimate x64 system. The network system setup is as follows: 2x XP Pro 32 Bit machines 1x Vista ultimate x64 machine 2x Windows 7 x64 Ultimate machines all chained into 1x 16 port netgear prosafe gigabit switch, the windows 7 & vista machines are duplexed. Also there is a router (netgear Rangemax) chained off the switch I am basically using one of the windows 7 machines to host storage & stream media to other machines. To this end i have put 2x 3tb hardware RAID 5 arrays in it and assorted other spare disks which i have shared the roots of. The unusual problems start when i am getting Access denied, Please contact administrator for permission blah blah blah when trying to access both of the RAID 5 arrays but not the other stand alones. I have checked the permission settings, i have added everyone to the read permission for the root, i have tried moving things into sub directories then sharing them. I have tried various setting combinations in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa and always the same. I have tried flushing caches all round, disabling and re-enabling shares & sharing after restart as well as several other things & the result is always the same... No problem on individual drives but access denied on both the RAID arrays from both XP & Vista & Windows 7 machines. One interesting quirk that may lead to an answer is that there is no "offline status" information regarding the folders when you select the RAID 5s from a windows 7 machine yet there is on the normal drives which say they are online. It is as if the raid is present but turned off or spun down but as far as i was aware windows will spin an array back up on network request and on the machine itself the drives seem to be online and can be accessed. Have to admit this has me stumped. Any suggestions anyone? Thanks in advance for any fellow geek assistance. K.A.I.N

    Read the article

  • How to improve network performance between two Win 2008 KMV guest having virtio driver already?

    - by taazaa
    I have two physical servers with Ubuntu 10.04 server on them. They are connected with a 1Gbps card over a gigabit switch. Each of these host servers has one Win 2008 guest VM. Both VMs are well provisioned (4 cores, 12GB RAM), RAW disks. My asp.net/sql server applications are running much slower compared to very similar physical setups. Both machines are setup to use virtio for disk and network. I used iperf to check network performance and I get: Physical host 1 ----- Physical Host 2: 957 Mbits/sec Physical host 1 ----- Win 08 Guest 1: 557 Mbits/sec Win 08 Guest 1 ----- Phy host 1: 182 Mbits/sec Win 08 Guest 1 ----- Win 08 Guest 2: 111 Mbits /sec My app is running on Win08 Guest 1 and Guest 2 (web and db). There is a huge drop in network throughput (almost 90%) between the two guest. Further the throughput does not seem to be symmetric between host and guest as well. The CPU utilization on the guests and hosts is less than 2% right now (we are just testing right now). Apart from this, there have been random slow downs in the network to as low as 1 Mbits/sec making the whole application unusable. Any help to trouble shoot this would be appreciated.

    Read the article

< Previous Page | 15 16 17 18 19 20 21 22 23 24  | Next Page >