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40

Processor advancements, clock speed and IPC calculations can make it almost impossible to try to reasonably compare decade old CPUs to modern ones. Not only are the instructions per cycle going to vary, but newer processors have instruction sets dedicated to complex calculations (Intel has added AES-NI as an example), clock speed is no longer a reasonable ...


31

I don't want to sound terrible by emphasizing something that should be obvious here, but you're comparing a high-end server processor from 2014 to a high-end server processor from 2007. I don't think this requires much more explanation. There's a reason an HP ProLiant DL580 G5 is available so inexpensively today. They were large, slow and lack many ...


22

1 x 10Gb link for performance. Otherwise if a single server needs to use 1.1Gbs to another server it can't because most load balancing systems use destination MAC or IP (Which would be the same). This also eliminates issues where links are busier then other links because of the same fact, if the hash works out to be on the same link they end up on the same ...


19

Is it ever sane to use a Virtualized solution when performing I/O heavy workloads? Yep, very sane indeed, in fact for most organisations now virtual is the default and doing things on physical boxes is the very much the exception. We have over 100k VMs of all forms and many of them are >40k IOPS with no issue at all. What are the best practices ...


10

Is it ever sane to use a Virtualized solution when performing I/O heavy workloads? Does a database server regularly pulling 1gb/second random IO count? Have one here. Or a virtual file server delivering up to 600mb/second to a HPC cluster. That one is running off 8 Velicoraptors in a Raid 10, dedicated. What are the best practices around this ...


6

somaxconn determines the maximum number of backlogged connections allowed for each TCP port on the system. Increasing it (recommended for servers) can prevent "connection refused" messages, but it can result in slow connections if the server can't handle the increased load. You can check the current backlog with netstat -ant | grep -c SYN_REC according to ...


4

Short answer: disable comp-lzo. I realize this is an old post, but I was also suffering from poor OpenVPN performance. I had tried everything, adjusting the MTU, changing the snd and rcv buffers, mss clamping, you name it. CPU load was negligible. On a whim, I disabled compression (removed comp-lzo from the client and the server) and performance increased ...


3

The HP H240 is not a RAID controller. It's a host bus adapter that's intended to provide direct disks access to a host operating system. This applies to people using software RAID, ZFS, Hadoop, Windows Storage Spaces, etc. It has some limited RAID capability, but as you can see, it's not sufficient. For VMware purposes, you want an HP Smart Array RAID ...


3

Use the 10 Gb/s link. Otherwise you restrict the VMs to 1 Gb/s when communicating with multiple clients or with other VMs (communication to other VMs should be through the virtual switch and not the physical NIC). If your network card supports it, use VMQ and / or SR-IOV. Ideally you should create an SR-IOV virtual NIC inside every VM. Most cards should be ...


2

The technique you want is called scientific method. With scientific method and some monitoring tools, you can diagnose the issue and take corrective action.


2

Using the log files has the added problem that they only contain completed requests and not the actively (long) running requests... Enable the Status module and you can query the web server directly for a live view: <Location "/server-status"> SetHandler server-status Require host localhost </Location> You can now access server ...


2

Besides the basic math & concept that you still need the same IOs as non-virtualised, there is also QOS/prioritisation. Most virtualisation platforms offer at least a basic support for this, will help out a lot to prevent the misbehaving dev VM stalling your prod DB.


1

Agree with Shodanshok that deadline is probably a good idea. Far from convinced that you should be using XFS here. find /volume/data/customer/ -type f -iname "*.ext" -mmin +60 -delete XFS used to be very bad with deleting files - I'm told that most of the bugs in this area have been resolved but not done any hard benchmarking to confirm this. it ...


1

First, XFS is the right choice for this kind if scenario: with XFS is almost impossible to go out of inodes. To increase your delete performance, try the following: use the deadline I/O scheduler rather the the (default) cfq use logbsize=256k,allocsize=64k as mount options (in addition to nodiratime,noatime) To lower the deletes impact on other system ...


1

As you already discovered, the low write speed had nothing to do with slow parity calculation (modern CPU are very fast at that), but was due to the disabled disk's private DRAM cache, and more precisely on how badly flash memory need it to give good sustained performance. I'll quote myself: Even my laptop's ancient CPU (Core i5 M 520, Westmere ...


1

Raid 5 always has poor write performance. I suggest to use Raid 10 but anyway did you installed the drivers for VMware ESXI from the HP website? Also consider to make a firmware update. If the Raid is still in the status of building/initializing the array performance is temporarily downgraded. This sometimes can take up to a couple of days if it'a full ...


1

You can use "ulimit" in the "start" section of the pgbouncer init script: /etc/init.d/pgbouncer: [... snip ...] case "$1" in start) # Check if we are still disabled in /etc/default/pgbouncer [ "${START:-}" = "0" ] && exit 0 log_daemon_msg "Starting PgBouncer" $NAME test -d $PIDDIR || install -d -o ...


1

From a system point of view, there is no inherent differences in running 4 masters with 4 server sections, or a single master with 16 server sections. It implements the same architecture : parallelized event-based processes. The worker/core ratio must be accounted wrt the total of workers across all of your masters if you have several ones. This comes from ...


1

As for performance, you must consider two aspects of it. First there is the processing performance in the server, and secondly the performance that end users experience. If you use any sort of redirect, whether by PHP or Apache's Redirect rule (which can be in .htaccess or Apache configuration file, end client must first wait for the first response ...



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