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  • Disk IO causing high load on Xen/CentOS guest

    - by Peter Lindqvist
    I'm having serious issues with a xen based server, this is on the guest partition. It's a paravirtualized CentOS 5.5. The following numbers are taken from top while copying a large file over the network. If i copy the file another time the speed decreases in relation to load average. So the second time it's half the speed of the first time. It needs some time to cool off after this. Load average slowly decreases until it's once again usable. ls / takes about 30 seconds. top - 13:26:44 up 13 days, 21:44, 2 users, load average: 7.03, 5.08, 3.15 Tasks: 134 total, 2 running, 132 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.1%sy, 0.0%ni, 25.3%id, 74.5%wa, 0.0%hi, 0.0%si, 0.1%st Mem: 1048752k total, 1041460k used, 7292k free, 3116k buffers Swap: 2129912k total, 40k used, 2129872k free, 904740k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1506 root 10 -5 0 0 0 S 0.3 0.0 0:03.94 cifsd 1 root 15 0 2172 644 556 S 0.0 0.1 0:00.08 init Meanwhile the host is ~0.5 load avg and steady over time. ~50% wait Server hardware is dual xeon, 3gb ram, 170gb scsi 320 10k rpm, and shouldn't have any problems with copying files over the network. disk = [ "tap:aio:/vm/dev01.img,xvda,w" ] I also get these in the log INFO: task syslogd:1350 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syslogd D 00062E4F 2208 1350 1 1353 1312 (NOTLB) c0ef0ed0 00000286 6e71a411 00062e4f c0ef0f18 00000009 c0f20000 6e738bfd 00062e4f 0001e7ec c0f2010c c181a724 c1abd200 00000000 ffffffff c0ef0ecc c041a180 00000000 c0ef0ed8 c03d6a50 00000000 00000000 c03d6a00 00000000 Call Trace: [<c041a180>] __wake_up+0x2a/0x3d [<ee06a1ea>] log_wait_commit+0x80/0xc7 [jbd] [<c043128b>] autoremove_wake_function+0x0/0x2d [<ee065661>] journal_stop+0x195/0x1ba [jbd] [<c0490a32>] __writeback_single_inode+0x1a3/0x2af [<c04568ea>] do_writepages+0x2b/0x32 [<c045239b>] __filemap_fdatawrite_range+0x66/0x72 [<c04910ce>] sync_inode+0x19/0x24 [<ee09b007>] ext3_sync_file+0xaf/0xc4 [ext3] [<c047426f>] do_fsync+0x41/0x83 [<c04742ce>] __do_fsync+0x1d/0x2b [<c0405413>] syscall_call+0x7/0xb ======================= I have tried disabling irqbalanced as suggested here but it does not seem to make any difference.

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  • Wireless traffic stops when downloading large files at high speed: packets lost (Linksys WRT120N router)

    - by Torious
    The problem Note: First I'd like to understand WHY this is happening. Ofcourse, a solution would be nice too. :) When downloading a large file over HTTP at high-speeds, my wireless traffic basically stops: I can't open webpages and the download itself pauses. It pauses pretty much immediately after starting it; sometimes at 800 KB, sometimes at a few MB. After some time, the download (and other traffic) resumes, but the problem keeps reoccurring during the same download. The problem does not occur when using a wired connection through the same router (Linskys WRT120N). Also note that the connection is not dropped when this happens. It's just that the traffic stops and I can't browse to web pages, etc. (SYN packets are sent but nothing is received, etc.) Inspection with Wireshark shows that the following happens: Server sends data packets which are acknowledged by client Server sends a packet, but SEQ indicates some packets were lost (6 packets in one occurrence). Server sends a few more packets and client acknowledges these using "selective acknowledgement" Server stops sending data for a while (since the lost packets were not acknowledged or the router stops forwarding them?) Eventually, server does a "retransmission" and traffic resumes as normal. This all seems normal behavior to me when packet loss occurs. It's the consistent packet loss throughout a large, high-speed download that puzzles me. What might cause this? My own idea is the following: My internet is pretty fast (100 mbps), so when starting a large-file download, the router buffers the incoming data (since wireless introduces some slight delay / lower speed, in part due to other networks), but the buffer overflows and the router drops packets to regulate traffic (and because it has no choice). But how could that happen? Doesn't the TCP window size limit the amount of data that can go unacknowledged? So how can the router's buffer overflow if there can only be like 64 KB waiting to be acknowledged? Note: I've disabled TCP window scaling and dynamic window size through netsh options, in an attempt to fix this, but it doesn't seem to matter. Also, Wireshark shows a pattern of the server sending 2 packets (of 1514 bytes) and the client sending an ACK, so does that rule out a possible buffer overflow? And a few more subsequent packets are received... I'm at a loss here. Thanks for any insights. Things that are (probably) NOT the cause / I have experimented with The browser Various TCP options in Windows 7 (netsh etc.) Router settings such as MTU, beacon interval, UPnP, ...

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  • Slow Write Speed on ESXi host

    - by Gregg Leventhal
    I have an ESXi 5.0 free host with an internal datastore of 7.2K 5 disk RAID 5 using a PERC 710 mini RAID controller in a Dell Poweredge R620 Server with 32GB Ram and a 12 Core Xeon. I seem to get slow write speeds in the guests so I checked out ESXTOP and I see 15MB/s write speed there on this host, which is comprable to the guests. What could be causing such horrible write speeds? Is RAID 5 really this slow to write??

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  • Handler_read_rnd is too high (more than 2GB)

    - by pnm123
    Hello, I am running an advertising program and there are some SELECT, UPDATE and DELETE queries when showing ads. Sometimes, displaying ads is fast but sometimes it is too slow. At this time, it is slow and Handler_read_rnd and Handler_read_rnd_next is as mentioned below. Handler_read_rnd 2,844.68 M Handler_read_rnd_next 2,945.63 M How can I speed-up displaying ads (decreasing Handler_read_rnd and Handler_read_rnd_next) Thank you, pnm123 PS: Currently there are 7,068,528 rows on the advertising program's database.

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  • windows 7 internet speed significantly slower than ubuntu

    - by Infestor
    i have windows 7 x64 and ubuntu 10.04 installed on my machine. while i download at ~15 MiB/sec in ubuntu (reaches almost at an instant), it takes almost a minute or two for win7 to reach that speed while downloading -say- a film. also the connection becomes unresponsive for some time periods in win7. i experienced this in several win7 installations (x64 prof. always, same version).

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  • Improve file transfer speed between Windows PCs and servers

    - by Geotarget
    I've setup a server which I've connected to multiple PCs in my workplace. Sadly, data transfer speeds are at max 3 MB/sec per connection which works out slow for file transfers, especially when transferring large files. I'm using Windows filesharing and the server is a Windows Server 2008 (2 Ghz CPU, 1 GB RAM) and the client PCs mostly running Windows 7. How can I detect bottlenecks in my network and improve file sharing speed within the network?

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  • Speed-up large number of files deletion on NTFS volumes

    - by sharptooth
    Every now and then I need to delete a folder containing something like 500k files from an NTFS volume. I do this with Windows Explorer. Since NTFS journals all the service data changes each deletion is carried out serially and so the whole 500k files deletion takes ages. I remember when I did the same in FAT32 it ran uncomparably faster. Is there any way to speed up deletion of large number of files on NTFS volumes?

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  • Maximise network transfer speed of various applications

    - by Alex
    When using nc, scp, wget to transfer files between 2 machines on a dedicated 2Mbps link, I get speeds between 0.5 and 1 Mbps. However, when I use iperf -c 10.0.1.4 -t 20 -P 12 (for example) I can maximise the speed of the link (getting stable 2Mbps). Is there a way to make single stream transfers (such as those done by scp) to utilise all/most of the link? Some kind of tcp settings, or iptables...?

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  • Current trends in Random Access Memory speed [closed]

    - by Vetal
    As I know for now because of laws of Physics there will be not any tangible improvements in CPU cycles per second for the nearest future. However because of Von Neumann bottleneck it seems to not be an issue for non-server applications. So what about RAM, is there any upcoming technologies that promise to improve memory speed or we are stack with the current situation till quantum computers will come out from labs?

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  • Is there software to automatically change song speed without transposing it

    - by Peter P
    Goal: automatically adjusting speed (bpm) of a given set of MP3 files in order to have a collection of music optimized to be heard when I am running. (I realized that I prefer to run with about 168 bpm in my ears). Of course, I could have some software to detect BPM and then calculate and stretch/squeeze each song using Audacity or a similar tool, however, I'd prefer a solution which requires less manual operation.

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  • Speed up MySQL for inserts (for testing purposes)

    - by Alex N
    I have a bit of software that needs to do a lot of INSERTs. In production environment there'll be some serious tweaking and testing and stuff like that, but now when I need to test it I'd like to speed up inserts as much as possible. Hence my question - is there a way to tweak mysql such that it doesn't do much disk I/O but keeps everything in RAM and syncs with disk rarely(like once n-seconds say?)

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  • Network speed between a VM and another machine which is not residing on the same host, is 11MB/s at most

    - by Henno
    Problem Network speed between a VM and another machine which is not residing on the same host, is 11MB/s at most. Topology Facts ESXi5 version is 5.0.0.504890 VM has the latest Vmware Tools installed VM is using E1000 network driver Physical box has Win Srv 2008 R2 as the OS CrystalDiskMark says the drive on physical box can read/write 100MB/s vCenter is another vm on esx both vm and physical box are showing 1Gbps link speed Configuration Networking shows vmnic0 as 1000 Full NTttcp is a client/server tool from Microsoft for measuring pure network throughput Here's what I've done so far: Test1: VM is running Filezilla FTP Server (default settings, one user account made) Physical box is running Filezilla FTP Client (default settings) Physical box is uploading a big file to FTP server Transfer speed (as observed by Windows Task Manager on both machines): ~11MB/s (bad) Physical box is downloading that file from FTP server Transfer speed (as observed by Windows Task Manager on both machines): still ~11MB/s (bad) Could it be disk performance issue? Test2: Physical box is running ntttcpr.exe -a 6 -m 6,0,VM_IP_ADDRESS VM is running ntttcps.exe -a 6 -m 6,0,PHY_BOX_IP_ADDRESS Transfer speed (as observed by Windows Task Manager on both machines): ~11MB/s (bad) Could it be switch performance issue? Test3: physical box is running vSphere Client I open Summary Storage datastore Browse Datastore... from physical box and upload a file to datastore Transfer speed (as observed by Windows Task Manager on physical box): ~26-36MB/s (good) Could it be a vm specific issue? Test4: Installed ntttcp to another vm on the same esx server Measured network performance between vms on the same esx server with NTttcp Transfer speed (as observed by Windows Task Manager on physical box): ~90-120MB/s (excellent :) Test5: I have another esx server on the same site, connecting to the same datastore and same switch. Those two ESX servers have both 2 NICs. One NIC goes to switch while the other goes directly to the other ESX server. vMotioned one of the testing vms off to the other ESX host Measured network performance between vms on different esx servers with NTttcp Transfer speed (as observed by Windows Task Manager on physical box): ~11MB/s (bad) While I'm aware of these: ESXi 4.1 slow file transfer ESXi 5 network performance is slow Debian Etch and ESXi slow network speeds VMWare ESXi slow file copy to guest they did not help (or I must have been missed something)

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  • Exchange 2010 DAG + VMWare HA = no support?

    - by Dan
    We currently have an Exchange 2003 clustered environment (two machine cluster) that we're looking to upgrade to 2010. We recently purchased a VMWare virtualization environment (three Dell R710's with an EMC NS-120 serving up NFS datastores - iSCSI is available) that we wish to use for this new environment. I'm seeing that Microsoft does not support Exchange 2010 DAGs with a virtualization high availability solution (see links below). I would like to utilize the DAG to ensure the data stays available if one host goes down, and HA to ensure that if the physical host goes down, the VM will come back up on the other available host. Does anybody know why MS does not support this? VMWare HA will only restart the VM if it is hung/down - I don't see any difference between this and restarting the physical box if someone pulled the power... Will we only run into issues with support if it has something to do with HA/DAG failover or will they see we have HA and tell us to put it on a physical box even if it has nothing to do with HA? If we disable HA for these VM's will that satisfy them on a support case? Has anybody set up an Exchange 2010 DAG on VMware with HA enabled? Will they have any issues with using an NFS datastore? We have much greater flexibility on the EMC with NFS vs iSCSI, so I would prefer to continue utilizing that. Thanks for any input! http://www.vmwareinfo.com/2010/01/verifying-microsoft-exchange-2010.html Take a look at the second image under "Not Supported" http://technet.microsoft.com/en-us/library/aa996719.aspx "Microsoft doesn't support combining Exchange high availability solutions (database availability groups (DAGs)) with hypervisor-based clustering, high availability, or migration solutions. DAGs are supported in hardware virtualization environments provided that the virtualization environment doesn't employ clustered root servers."

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  • Oracle Application Server Performance Monitoring and Tuning (CPU load high)

    - by Berkay
    Oracle Application Server Performance Monitoring and Tuning (CPU load high) i have just hired by a company and my boss give me a performance issue to solve as soon as possible. I don't have any experience with the Java EE before at the server side. Let me begin what i learned about the system and still couldn't find the solution: We have an Oracle Application Server (10.1.) and Oracle Database server (9.2.), the software guys wrote a kind of big J2EE project (X project) using specifically JSF 1.2 with Ajax which is only used in this project. They actively use PL/SQL in their code. So, we started the application server (Solaris machine), everything seems OK. users start using the app starting Monday from different locations (app 200 have user accounts,i just checked and see that the connection pool is set right, the session are active only 15 minutes). After sometime (2 days) CPU utilization gets high,%60, at night it is still same nothing changed (the online user amount is nearly 1 or 2 at this time), even it starts using the CPU allocated for other applications on the same server because they freed If we don't restart the server, the utilization becomes %90 following 2 days, application is so slow that end users starts calling. The main problem is software engineers say that code is clear, and the System and DBA managers say that we have the correct configuration,the other applications seems OK why this problem happens only for X application. I start copying the DB to a test platform and upgrade it to the latest version, also did in same with the application server (Weblogic) if there is a bug or not. i only tested by myself only one user and weblogic admin panel i can track the threads and dump them. i noticed that there are some threads showing as a hogging. when i checked the manuals and control the trace i see that it directs me the line number where PL/SQL code is called from a .java file. The software eng. says that yes we have really complex PL/SQL codes but what's the relation with Application server? this is the problem of DB server, i guess they're right... I know the question has many holes, i'd like to give more in detail but i appreciate the way you guide me. Thanks in advance ... Edit: The server both in CPU and Memory enough to run more complex applications

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  • Network Transfer Rate on SMB/FTP

    - by Jack Sleight
    Hi, We're trying to optimise our network transfer rate from the client PCs to the file server, but having no luck. If I run an iperf test between a client PC (Windows XP) and our server (Linux) with a large TCP window size (the default is 8kb) I can get 60 Mbps. But when I run an SMB transfer speed test all I get is around 35 Mbps. When I run an FTP transfer speed test all I get is around 32 Mbps. I thought this was to do with the TCP window size, but I have now increased that to 256960 and it made no difference at all. Any ideas what I'm doing wrong? Or is 35 Mbps all I should expect? Cheers, Jack

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  • Vertex 2 SSD is running faster than my Vertex 3 SSD?

    - by Kairan
    I used Acronis Disk Director to do a direct clone of my C:\ windows 7 x64 drive from my Vertex 2 to my new Vertex 3 SSD (Just to show the drive software winstall everything is identical.) I ran a performance test on Windows using the Windows Experience Index. The rating I am receiving when booting on the Vertex 2 is 7.5 While I am getting only a rating for the Vertex 3 of 6.9 My understanding is that the read/write speeds of the Vertex 2 is only up to 250MB/sec while the Vertex 3 is up to 500MB/sec. Copying a single file (3GB in size) from the Vertex 3 to itself was getting speed of approx 70-80MB/sec This speed is no better (maybe worse) than what I got from the Vertex 2 I am connected via the SATA 3 port on the motherboard, using an SATA 3 cable Is this issue caused by the drive cloning? Do I have a bad SSD?

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  • MP3 player mpman TS300 not recognized

    - by Nick Lemaire
    I just received a mpman ts300 mp3 player for Christmas. But when I try to connect it to ubuntu (10.10) through usb it doesn't seem to be recognized. I searched for a linuxdriver but came up with nothing. I even tried installing mpman manager from the software center, but still the same problem... Has anybody got any ideas about how to fix this? Thank you edit: some additional information When I plug it in, it doesn't show up under /dev. And it is not listed in the result of 'lsusb' This is the output of 'dmesg' [19571.732541] usb 1-4: new high speed USB device using ehci_hcd and address 2 [19571.889154] scsi7 : usb-storage 1-4:1.0 [19572.883155] scsi 7:0:0:0: Direct-Access TS300 USB DISK 1.00 PQ: 0 ANSI: 0 [19572.885856] sd 7:0:0:0: Attached scsi generic sg2 type 0 [19572.887266] sd 7:0:0:0: [sdb] 7868416 512-byte logical blocks: (4.02 GB/3.75 GiB) [19573.012547] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19573.292550] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19573.572565] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19573.725019] sd 7:0:0:0: [sdb] Test WP failed, assume Write Enabled [19573.725024] sd 7:0:0:0: [sdb] Assuming drive cache: write through [19573.728521] sd 7:0:0:0: [sdb] Attached SCSI removable disk [19575.333015] sd 7:0:0:0: [sdb] 7868416 512-byte logical blocks: (4.02 GB/3.75 GiB) [19575.452547] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19580.603253] usb 1-4: device descriptor read/all, error -110 [19580.722560] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19595.842579] usb 1-4: device descriptor read/64, error -110 [19611.072656] usb 1-4: device descriptor read/64, error -110 [19611.302540] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19616.332568] usb 1-4: device descriptor read/8, error -110 [19621.462692] usb 1-4: device descriptor read/8, error -110 [19621.692551] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19626.722567] usb 1-4: device descriptor read/8, error -110 [19631.852802] usb 1-4: device descriptor read/8, error -110 [19631.962587] usb 1-4: USB disconnect, address 2 [19631.962587] sd 7:0:0:0: Device offlined - not ready after error recovery [19631.962840] sd 7:0:0:0: [sdb] Assuming drive cache: write through [19631.965104] sd 7:0:0:0: [sdb] READ CAPACITY failed [19631.965109] sd 7:0:0:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [19631.965112] sd 7:0:0:0: [sdb] Sense not available. [19631.965125] sd 7:0:0:0: [sdb] Assuming drive cache: write through [19631.965130] sdb: detected capacity change from 4028628992 to 0 [19632.130042] usb 1-4: new high speed USB device using ehci_hcd and address 3 [19647.242550] usb 1-4: device descriptor read/64, error -110 [19662.472560] usb 1-4: device descriptor read/64, error -110 [19662.702566] usb 1-4: new high speed USB device using ehci_hcd and address 4 [19677.822587] usb 1-4: device descriptor read/64, error -110 [19693.052575] usb 1-4: device descriptor read/64, error -110 [19693.282582] usb 1-4: new high speed USB device using ehci_hcd and address 5 [19698.312600] usb 1-4: device descriptor read/8, error -110 [19703.442594] usb 1-4: device descriptor read/8, error -110 [19703.672548] usb 1-4: new high speed USB device using ehci_hcd and address 6 [19708.702581] usb 1-4: device descriptor read/8, error -110 [19713.840077] usb 1-4: device descriptor read/8, error -110 [19713.942555] hub 1-0:1.0: unable to enumerate USB device on port 4 [19714.262545] usb 4-2: new full speed USB device using uhci_hcd and address 2 [19729.382549] usb 4-2: device descriptor read/64, error -110 [19744.612534] usb 4-2: device descriptor read/64, error -110 [19744.842543] usb 4-2: new full speed USB device using uhci_hcd and address 3 [19759.962714] usb 4-2: device descriptor read/64, error -110 [19775.200047] usb 4-2: device descriptor read/64, error -110 [19775.422630] usb 4-2: new full speed USB device using uhci_hcd and address 4 [19780.444498] usb 4-2: device descriptor read/8, error -110 [19785.574491] usb 4-2: device descriptor read/8, error -110 [19785.802547] usb 4-2: new full speed USB device using uhci_hcd and address 5 [19790.824490] usb 4-2: device descriptor read/8, error -110 [19795.961473] usb 4-2: device descriptor read/8, error -110 [19796.062556] hub 4-0:1.0: unable to enumerate USB device on port 2

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  • Which is faster? 4x10k SAS Drives in RAID 10 or 3x15k SAS Drives in RAID 5?

    - by Jenkz
    I am reviewing quote for a server upgrade. (RHEL). The server will have both Apache and MySQL on it, but the reason for upgrade is to increase DB performance. CPU has been upgraded massively, but I know that disk speed is also a factor. So RAID 10 is faster performance than RAID 5, but how much difference does the drive speed make? (The 15k discs in the RAID 5 config is at the top of my budget btw, hence not considdering 4x15k discs in RAID 10, which I assume would be the optimum.)

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  • Slower than expected 802.11n wireless network speeds

    - by Ian
    I have two ASUS laptops running Windows 7 connected wirelessly via 802.11n at 150 Mbit, as reported by Task Manager. The router is Netgear WNDR3700. When testing the wireless connection speed using iperf, I'm not getting nearly 150 Mbit: C:\>iperf -c 10.0.0.123 -t 30 ------------------------------------------------------------ Client connecting to 10.0.0.123, TCP port 5001 TCP window size: 8.00 KByte (default) ------------------------------------------------------------ [148] local 10.0.0.116 port 53819 connected with 10.0.0.123 port 5001 [ ID] Interval Transfer Bandwidth [148] 0.0-30.0 sec 41.2 MBytes 11.5 Mbits/sec That's a typical result. Running parallel client threads does not increase the overall total speed. Why would I only be getting 11.5 Mbit on a 150 Mbit connection?

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  • Investigate high load on RHEL

    - by Adam Matan
    One of my RHEL 5 was showing high load (~4-5) on uptime. The load increased, and when it reached 6 (±), the server froze and needed restart. top-wise, the server had no significant CPU or memory issues and sar showed no increase in iowait. Therefore, the thrashing must have been related to other factors. Any ideas how to investigate this? In particular, how do I know that which processes are waiting in the queue?

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  • Amazon EC2 High-Memory Extra Large Instance

    - by Simpanoz
    I am new to Mongodb and EC2. If I use following single MongoDb server : High-Memory Extra Large Instance 17.1 GiB memory, 6.5 ECU (2 virtual cores with 3.25 EC2 Compute Units each), 420 GB of local instance storage, 64-bit platform As a layman, if we quantify I/O, data in MB/sec. How much I/O transactions mongodb server can handle easily, without being burnt out. Consider default settings of EC2 server with Ubuntu and MongoDb version available in AWS marketplace. Thanks in advance

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