how to defragment

Structure table1.myd storing data table1.myi Storing indexPerform regular optimize table T1 to improve performance and defragment disk space The MyISAM table also supports different storage formats in 3: 1 static table 2 dynamic table 3 compression table static tables are the default storage format, and fields in static tables are non-variable-length fields, with the advantage that storage is very fast, easy to cache, failures are ea

$last =count ($arr);$arr[0 is usually ignored in heap sorting]Array_unshift ($arr, 0);Last Non-leaf node$i = $last >>1; Organize into a large top heap, the largest number to the top of the heap, and the maximum number and the end of the heap exchange, and in the subsequent calculation ignores the maximum number of array backend (last), until the heap top (last= heap top)while (true){Adjustnode ($i, $last, $arr);if ($i >1){Move node pointer, traverse all non-leaf nodes$i--;}Else{Critical point La

vro, select [Y], but the prerequisite is that there are two NICs, one for the external network and the other for the internal network, in addition, you must set the routing at the end of the ISP to allow the user to access this vro. IP: multicasting: transfers a packet to several computers at a time. IP: syn_cookies: a protection measure that encrypts various TCP/IP communication protocols, prevents Attacker from attacking users' computers, and records IP addresses of computers attempting to at

method escape, and may even be accessed by an external thread. For example, assignment to a class variable or an instance variable that can be accessed in another thread is called a thread escape.How to prove that an object does not escape to a method or thread, that is, the method or threads cannot access the object by any means, it is possible to perform some efficient optimizations for this variable, such as:Stack allocation: In a Java Virtual machine, multiple rows of the Java heap allocate

what advantages and disadvantages.Analysis: Also read the "Deep JVM virtual machine" Basic can answer this degree, in fact, to this extent I have been more than expected. Also less than 10%.4. In addition to 3, can also be clear serial, parallel (collation/Not defragment), CMS, such as the role of the collector can be the age, characteristics, advantages and disadvantages, and can explain the control/adjustment of the collector selection method.Analy

-vdiskmanager-x 6 GB "D:/virtual MacHines/SUS/Windows 2000 Professional (2). vmdk" Parameter-X indicates that the disk space of the virtual machine is to be extended. The following number indicates the size of the disk to be extended (such as 12 GB, indicating the total disk volume, including the original disk capacity) Refer:VMware Virtual Disk Manager-build 12544.Usage: vmware-vdiskmanager.exe options diskname | drive-letter:Offline disk manipulation UtilityOptions:-C: create disk; need to sp

accessing some files or directories. Currently the driver does not implementDefragging support. So defragmentation applications will neither show fragmentation information nor defragment any Ext2 volume. This software does not achieve booting a Windows operating system from an Ext2 volume. LVM volumes are not supported, so it is not possible to access them. 4. DiskInternals Linux Reader for Windows (http://www.diskinternals.com/linux-reader) Suppo

The interface does not provide a way to increase the disk capacity. It can only be executed in the form of command lines. There is a vmware-vdiskmanager.exe under the Program Files \ VMware workstationto install the disk. The command parameters are as follows:------------------------------------------------------------------Usage: vmware-vdiskmanager.exe OPTIONS Offline disk manipulation utility Options:-C: create disk; need to specify other create options-D:

| drive-letter:Offline disk manipulation UtilityOptions:-C: create disk; need to specify other create optionsCreate a new disk-D: defragment the specified Virtual DiskDisk fragmentation-K: shrink the specified Virtual DiskCompress a specified Disk-N Specify destination disk-nameRename a disk-P: Prepare the mounted Virtual Disk specifiedThe drive-letter for shrinking-Q: Do not log messages-R Destination disk-typeConvert Disk Type-X Expand disk capacit

Http://blog.csdn.net/bshawk/archive/2008/01/28/2070587.aspx When I recently compiled the kernel 2.6.22, I found that the FC6 hard disk space on the virtual machine was insufficient. As a result, I wanted to expand the hard disk size. After checking the information, someone on the Internet said that a new. vmdk would be created and mounted to FC6. I personally think this method is not good. Is there a way to directly expand the size of the original vmdk. After checking some information, click "

, and records IP addresses of computers attempting to attack users.IP: firewalling: whether the computer is a firewall serverIP: Firewall packet logging: whether the klogd records the packets received by the firewall server.IP: Masquerading: Packets sent from computers in the internal network can be directly transmitted to remote computers through the firewall server, what remote computers see is the packets sent from the firewall server rather than from the internal computer. In this way, if on

1 Conceptual UnderstandingDue to the frequent DML operations on the table space, some space debris is bound to affect the system efficiency in space allocation. The methods you can use to defragment your disk are rebuild tables, move, shrink, and so on. Another case is that the delete operation does not reclaim the HWM high watermark, while the Oracle Scan table is still scanned from the 1th block of data to HWM, and when a new record is inserted, it

level ),At the same time, the data position on the partition is re-ordered, which is equivalent to defragment,Test 1: Write $ MFT in the left and right locations of the partition (refer to the location of ghost restoration and take the same location as Ghost restoration)Test 2: Write $ MFT at the beginning of partition, for example, 0x4000.Other files, such as $ mftmirr and $ logfile, are all written after $ MFT in sequence.Neither Test 1 nor Test 2

mode usually can play a certain recovery function in the case that the system boot file or the core configuration has been cut off, if can enter the system smoothly to eliminate , if the failure is still considered the reload system. 3, enter the system abnormally slow, near-dead condition This is mainly due to the fact that abnormal hardware or system spam is detected in the system boot process Workaround: Confirm that there is an exception to a disconnected peripheral, mount too many drive

easily lead to system application paralysis ). For "> RHEL4. added the VM. lower_zone_protection parameter. The default unit of this parameter is mb. The default value is 0, and the lowmem value is 16 Mb. We recommend that you set VM. lower_zone_protection = 200 or greater to avoid fragments in the lowmem region. This parameter can solve this problem ). For "> RHEL3 (kernel 2.4) does not seem to be a good solution. One is to use the hugemem kernel (heaven knows if it will introduce new issues),

in the backgroundUsing idle CPU time only, and is able to defragment SQL server filesWhile they are in use. Your mileage may vary, but I have seenStaggering improvements from running this tool.I/O Configuration Other best practice includes splitting tempdb into several files,Putting data and log files on separate disks, placing clustered andNon-clustered indexes in separate filegroups (on different disks ),Keeping statistics up-to-date, etc.All these

thread consumes memory that is not particularly large, you can properly raise the-xx:cmsinitiatingoccupancyfraction to reduce the number of GC times and improve performance, if the reserved user thread memory is not enough, it will trigger concurrent Mode Failure, At this point, the fallback scenario will be triggered: collect using the serial old collector, but the pause time is long, so the-xx:cmsinitiatingoccupancyfraction should not be too large. Also, the CMS uses a markup cleanup algorith

time will generally be slightly longer than the initial marking phase, but much shorter than the time of the concurrent tag. because the collector thread can work with the user thread during the longest concurrent markup and concurrent cleanup process throughout the process, the overall The memory recycling process for the CMS collector is performed concurrently with the user thread. Old age collectors (new generation using parnew) Benefits: Concurrent collection, low pauses drawbacks: gener

between the app and screen compositor, and Cursor buffers shares memory between content provider and clients. 2) Allocating and recovering memory The Dalvik heap for each process reflects the footprint of using memory. This is the usual logical reference to the Dalvik Heap Size, which can grow as needed, but the growth behavior will have an upper limit set by the system. The logical heap size and the actual physical sense of memory used are not equal, proportional Set size (PS

: TextView Android:layout_width = "Wrap_content" android:layout_height= "Wrap_content" android:text= "@string/test_alt_ Enter " android:maxlines=" 1 " android:textsize=" 36SP " />Also, the corresponding code is automatically generated in the String.xml file, as shown in:name= "Test_alt_enter"> Test alt+enterstring >2, the string written in the Java file, organized into String.xmlAnd the string that is written in the layout file, the way it is organized in