Ummy video downloader 1 67 – the simplest video downloader. Note this page is out-of-date!!!
The excess amount of RAM on your system, mostly unused, can be used to create a RAM Drive or RAM Disk. You can take its advantage to reduce application load times, improve performance while. In order to create a VHD on Windows 10, do the following: Open Start. Search for Disk Management and click the top result to launch the experience. Click the Action button. Click the Create VHD.
See cache strategy for the caching architecture we use. It's critical to site performance and understanding the roles of the systems described here.
The original document was written in late September of 2004. An update on October 11th of 2004:
Our next order[edit]
For early October we anticipate ordering one 'set' of computers, A set is a fairly balanced mixture of one Squid cache server, four or five Apache web servers and one database slave. We expect to add sets like this as needed, adjusting the exact balance as necessary.
From the vendor we have been using, we'd order this:
If we were looking to buy from IBM, we'd be investigating the Cluster 1350 system.
Question - don't you think a UPS system would also be a wise investment?
Our growth rate[edit]
. As of December 2004 it has 39 servers.
The performance limited doubling time was about 20 weeks, the recent one about 8 weeks. Ignoring anticipated software improvements, the possibility that we would reach the limit of demand for what we offer and cost considerations, the 8 week doubling time would see us having over 1,000 computers by September 2005.
Background information[edit]
For longer term capacity growth we will need to expand in these general areas. For all areas, we want at least three systems. People are relying on our presence as the emerging encyclopedia of the Internet and we don't want to be unavailable.
Database[edit]
The database architecture has a general master/slave setup, with roles split across the group. For all but the search servers, the system must be capable of allocating most of the system RAM in a single chunk because MySQL's InnoDB engine makes a single allocation for its cache. We currently use Opteron systems with Fedora Core 2.
Web servers/page builders[edit]
These read from the databases and produce the final web pages. Parsing the wiki text is CPU-intensive in PHP and the per-page rendering times are in the 300ms and up range. Caching is used to reduce the need to do this repetitively, so longer term the main load from this is to support those editing articles, who need repeated parsing to preview their work. Ideal for this role would be blade servers with RAM in the 512MB to 1-2GB range and small disks of any speed. It's a pure CPU power and rack space efficiency game. For redundancy, if blade servers are used, we'd want to start with at least three, possibly partially filled, so we won't hurt unduly if one fails. Alternatively, one rack unit single or multiple CPU boxes are well suited to this role. We're currently using single CPU P4s with RAM in the 512MB-2GB range. Disks are likely to be a long term reliability liability. We use Memcached for caching at present and it shares the RAM with the Apache web servers. We're in the early stages of testing a caching BDB database backed alternative, which may allow the use of disk rather than RAM, though perfection would be enough RAM to cache several versions of every article in this web server farm. Unlikely to be economic to do that as size grows but the more inexpensive RAM the caching system has, the better. We currently use 6GB of this cache and have 10GB of article text. Skins vary and aren't yet fully done via CSS, so space for several copies would be useful, though at steadily reducing efficiency as the size grows.
Media storage[edit]
We have recently purchased a 1TB RAID 5 box to handle our storage needs for images and eventually more multimedia. This is estimated to be sufficient for 6-12 months. We're likely to want several more. This has modest write loads. RAID 5 IDE arrays or network attached storage systems are ideal. As always, three or more are desired for redundancy.
Squid cache servers[edit]
We use these to serve about 80% of all hits. The software is single threaded, so single CPU systems are all that is necessary. CPU load and response time rises with the number of simultaneous connections to be serviced, so a fair number of moderately capable systems, each with relatively few connections to service, should do better than many big systems. RAM for caching is shared between these. We currently use four single CPU P4s with 4GB of RAM and slow IDE drives. Squid is reported to do well with a large number of very small drives, since it spreads its disk caching load across them all. We've no experience with this. For load surges from media attention, experience and benchmarks have shown that the Squids can easily serve the pages quickly from cache, provided the total number of simultaneous connections doesn't become excessive. For our normal load we tested switching more and more load to one Squid and found that performance would start to suffer significantly as the total number of cache misses it saw rose. So, our typical load handling capability is fairly well measured by CPU use, with some margin above 100% use where page serving times start to degrade at an increasing rate. We expect to locate Squid sets of three or more machines in various locations around the world, using donated hosting and bandwidth. We use Squid 2 and are planning to evaluate Squid 3, which has some architectural improvements (better polling) which may significantly raise the simultaneous connection capacity of each machine.
Load balancing[edit]
We currently do DNS-based load balancing to the Squids and ping-type response time measurement to determine which Apache should service the request. This is currently sensitive to both network topology and speed differences between individual systems, though it steadies down and balances more evenly as load rises. Software changes which factor in current CPU load on the web servers rather than solely their response time are on the to do list. Hardware based load balancing would be helpful.
The current implementation of Squid to Apache load balancing uses the Squid ICP (Inter Cache Protocol), which requires an actual Squid server running on each Apache. A project is currently in progress, and showing much promise, to replace this vestigial Squid with a customized client which will reply to the actual Squid servers with a more finely tuned indication of Apache server load.
Backup[edit]![]()
We do not yet have an adequate backup system. We copy the databases to local disks in the same racks as the main systems. As offers and/or purchases allow we'll be using some form of off site database backup, likely via continuous replication to one or more sites. Local backup may best be handled by network attached storage or large RAID systems with cheap drives or a near line storage setup of some sort. Today we use duplicate copies on inexpensive IDE drives in the web servers and multiple database slaves.
Development platforms, human factors[edit]
We do not yet have an adequate development test system and interpersonal communications could be improved further:
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Creates a new virtual disk in the specified storage pool.
SyntaxIramdisk 3 6 8 – Create A Ram Disk Capacity UpgradeDescription
The New-VirtualDisk cmdlet creates a new virtual disk in the specified storage pool.
ExamplesExample 1: Creating a 100 GB virtual disk using default settings
This example creates a virtual disk named UserData from the storage pool named CompanyData that is 100GB in size, using the storage pool default settings for unspecified parameters.
Example 2: Creating a thinly-provisioned mirror
This example creates a virtual disk named DataWarehouse, which is 42TB in size, uses the Mirror resiliency setting, and is thinly provisioned.
Example 3: Creating a three-way mirror
This example creates a 42 TB thinly-provisioned virtual disk on the Windows Storage subsystem, using the Mirror resiliency setting with three data copies.This creates a three-way mirror that is capable of tolerating two disk failures).
Example 4: Creating a two-column mirror
This example creates a thinly-provisioned virtual disk on the Windows Storage subsystem that uses two columns, regardless of how many physical disks are in the storage pool above the two-disk minimum for a two-way mirror.
Example 5: Create a mirror space with storage tiers
This example creates a 40 GB fixed provisioning virtual disk on the Windows Storage subsystem.The virtual disk uses the Mirror resiliency setting and storage tiers to store 8 GB of data on the SSD tier and 32 GB of data on the HDD tier.
Example 6: Create a dual-parity space
This example creates a virtual disk on the Windows Storage subsystem that uses the dual-parity resiliency type to help protect against two simultaneous disk failures and maximize capacity efficiency.
Parameters
Specifies the allocation unit size to use when create the virtual disk.
Runs the cmdlet as a background job. Use this parameter to run commands that take a long time to complete.
Specifies that the number of columns used by the virtual disk should be automatically determined.Columns represent the number of underlying physical disks across which one stripe of data for a virtual disk is written.
Indicates that the cmdlet sets the size of the write-back cache to 1 GB for all types of storage spaces, which include simple, mirror, and parity, to create from the pool.If the number or size of the solid-state drives (SSDs) or journal disks in the storage pool is not sufficient and you specify a value of $True for this parameter, the cmdlet sets the write-back cache size to 0 for simple and mirror spaces, and to 32 MB for parity spaces.
Runs the cmdlet in a remote session or on a remote computer.Enter a computer name or a session object, such as the output of a New-CimSession or Get-CimSession cmdlet.The default is the current session on the local computer.
Specifies at which level columns within a virtual disk should be isolated from each other.We recommend omitting this parameter and using the defaults.The acceptable values for this parameter are:
Specifies at what level you want the virtual disk to be fault tolerant.The acceptable values for this parameter are:
For example, specify StorageScaleUnit to store data copies on separate nodes of a Storage Spaces Direct cluster.This cmdlet refers to nodes of a Storage Spaces Direct cluster as storage scale units because you can expand the scale of the cluster by adding more nodes.
Specifies the friendly name for the virtual disk.The friendly name is not required to be unique.
Specifies the input object that is used in a pipeline command.
Specifies the interleave value to use during the creation of a virtual disk.The interleave value represents the number of bytes that is written to a single physical disk.Therefore,
Interleave * NumberOfColumns yields the size of one stripe of user data.
Specifies that the virtual disk should use enclosure awareness.
To support deployments that require an added level of fault tolerance, Storage Spaces can associate each copy of data with a particular just-a-bunch-of-disk (JBOD) enclosure.This capability is known as enclosure awareness.With enclosure awareness, if one enclosure fails or goes offline, the data remains available in one or more alternate enclosures.
To use enclosure awareness, you must use JBODs that are certified for use with Storage Spaces and you must have a sufficient number of JBODs and disks to support the resiliency types of the storage spaces you create (generally you'll need three or four JBODs).For a list of certified JBODs, see the Windows Server Catalog.For more information about enclosure awareness, see Storage Spaces Frequently Asked Questions.
Specifies the media type of the storage tier.The cmdlet creates the storage tier for the media type that you specify.The acceptable values for this parameter are:
Use SCM for storage-class memory such as NVDIMMs.
Specifies the number of columns to use when allocating the virtual disk.
Specifies the number of data copies to create.Specify 2 to create a two-way mirror, or 3 to specify a three-way mirror or for dual parity.
specifies the number of groups used by Local Reconstruction Coding (LRC) with a dual parity virtual disk.We recommend omitting this parameter and using the defaults.
Specifies an OtherUsageDescription string for the virtual disk.You can use the OtherUsageDescription parameter only if you set the Usage parameter to Other or do not include the Usage parameter.
Specifies the physical disk redundancy value to use during the creation of a virtual disk.This value represents how many failed physical disks the virtual disk can tolerate without data loss.
Specifies an array of one or more PhysicalDisk objects.The PhysicalDisk objects represent the specific physical disks on which to create this virtual disk.
Specifies the type of provisioning.The acceptable values for this parameter are:Fixed, or Thin.You must specify Fixed for storage spaces that use storage tiers or a clustered storage pool.
Iramdisk 3 6 8 – Create A Ram Disk Capacity For A
This parameter is no longer supported.
Specifies the resiliency setting, or storage layout, to use for the virtual disk.Acceptable values vary by storage subsystem.
Allowed values for the Windows Storage subsystem are: Simple, Mirror, or Parity.By default, when you specify Mirror, Storage Spaces creates a two-way mirror, and when you specify Parity, Storage Spaces creates a single-parity space.
To create a three-way mirror space, specify 3 for the NumberofDataCopies parameter or 2 for the PhysicalDiskRedundancy parameter.
To create a dual-parity space, specify 2 for the PhysicalDiskRedundancy parameter and Fixed provisioning for the ProvisioningType parameter.
Specifies the size of the virtual disk to create.The default unit is Bytes; to specify a different unit, enter the size followed by one of the following unit values, with no spaces: Bytes, KB, MB, GB, or TB.
Iramdisk 3 6 8 – Create A Ram Disk Capacity Ratio
Specifies the friendly name of the storage pool in which to create the virtual disk.Enter a friendly name, or use wildcard characters to enter a name pattern.
Specifies the name of the storage pool in which to create the virtual disk.Enter the name of the storage pool provided by the Storage Management Provider, or use wildcard characters to enter a name pattern.
Specifies the ID of the storage pool in which to create the virtual disk Enter an ID or use wildcard characters to enter a pattern.
Specifies an array of storage tiers as a CIMInstance object.The cmdlet adds the storage tiers that you specify to the virtual disk.To obtain a virtual disk object, use the Get-StorageTier cmdlet.
Specifies an array of sizes of the storage tiers that you specify for the StorageTiers parameter.
Specifies the maximum number of concurrent operations that can be established to run the cmdlet.If this parameter is omitted or a value of
0 is entered, then Windows PowerShell® calculates an optimum throttle limit for the cmdlet based on the number of CIM cmdlets that are running on the computer.The throttle limit applies only to the current cmdlet, not to the session or to the computer.
Specifies the intended usage of the virtual disk.You can specify one of the predefined descriptions, or use the default value (Other) and instead use the OtherUsageDescription parameter to specify a custom value.
Iramdisk 3 6 8 – Create A Ram Disk Capacity Upgrade
Creates a virtual disk with the maximum size possible given the available storage pool space and specified parameters.
Specifies the size of the write-back cache.The cmdlet creates the write-back cache of the size that you specify when the cmdlet creates the virtual disk space.
The following describes the behavior of this parameter based on the value that you specify:
InputsHow To Create A Ram Disk
You can use the pipeline operator to pass an MSFT_StoragePool object to the InputObject parameter.
You can use the pipeline operator to pass an array of MSFT_StorageTier objects to the StorageTiers parameter.
Iramdisk 3 6 8 – Create A Ram Disk Capacity DriveOutputsIramdisk 3 6 8 – Create A Ram Disk Capacity Chart
The New-VirtualDisk cmdlet returns an object that represents the newly created virtual disk.
Notes
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