你的位置：国外/美国服务器租用→ 国外服务器常见问题→ 正文
美国服务器出租
  1. 1美国独立服务器10G独享带宽不限流量，欧洲1G带宽独享，不限流量
  2. 2美国100M独享，洛杉矶 32GB内存 英特尔至强CPU，特价：1699元/月
  3. 3美国加州机房100M独享E3-1270，32G内存/96G内存，送KVM，1399元/月
  4. 4美国云服务器，8G内存,服务器CPU,4核心,特价699元/月,16G内存1299元
  5. 5美国G口抗攻击服务器，G口1000M独享带宽抗DDOS攻击服务器(至强Xeon E3 1230)
  6. 6国外G口带宽独享服务器，美国G口独享，欧洲G口独享服务器租用
  7. 7美国圣安娜KT服务器，加州KT服务器租用，KT独立服务器出租(特价799元/月)
  8. 8加州洛杉矶机房，中国访问速度最快的美国机房之一，999元/月，4G内存20M独享
  9. 9美国1G独享带宽，欧洲1G独享带宽租用（视频等大流量网站解决方案）
  10. 10凤凰城机房Phoenix服务器租用:7个机房4核I3，8G内存,30M独享带宽,首月999元
更多...
美国VPS主机
  1. 1美国SSD VPS租用，美国西海岸加州洛杉矶SSD VPS服务器,Linux/Windows
  2. 2内华达州VPS，拉斯维加斯VPS，拉斯维加斯服务器，内华达州服务器租用
  3. 3美国东海岸VPS，纽约服务器，曼哈顿云服务器，纽约VPS租用
  4. 4外贸VPS服务器，仿牌空间，仿牌主机，抗投诉VPS（外贸英文商城VPS）SSL证书安装服务
  5. 5美国Psychz电信直连VPS,中国访问速度最快的美国VPS,Psychz机房VPS
  6. 6Camforg专用VPS,美国Camforg多视频聊天软件VPS,Camforg服务器租用
  7. 7美国加州VPS，洛杉矶WebNX机房VPS，加州WN机房Windows VPS
  8. 8美国西雅图VPS，西雅图机房VPS，支持试用的VPS，VPS试用10元/天
  9. 9合租美国服务器，国外服务器合租，高端VPS服务器，完胜低配独立服务器的VPS
  10. 10抗攻击Windows VPS，不怕DDOS攻击的VPS，有攻击不关机，无攻击后2小时内恢复
更多...
软件raid和硬件raid的区别，软raid和硬raid有什么不同？

  • 软raid和硬raid有什么不同？从安装过程来看，两种RAID解决方案的安装过程都比较容易，安装耗时也相差无几。从CPU占有率来看，基于硬件的RAID显然能够减少CPU的中断次数，同时降低主PCI总线的数据流量。从而是系统的性能产生一个提升。从I/O占用角度考虑，两种解决方案的差别并不算很大。基于硬件的RAID方案仅在下列两方面有一定优势；减少RAID5阵列在降级模式的运行时间；平行引导阵列的能力。另外，在硬件解决方案中，可以采用RAID0/1 取代RAID1来提高性能。尽管基于硬件的RAID 方案具有优势，但在产品的价格上仍然无法与基于软件的RAID抗衡--后者完全免费。不过，硬件解决方 案的价格也不是不可接受，一般只需增加少许投资即可获得一套基于硬件入门级RAID解决方案。而基于软件的RAID解决方 案也不是分文不花，至少还需购置一块SCSI卡。因此，在计算总体拥有成本是，必需考虑基于软件的RAID解决方案的隐性成本，如用户生产效率、管理成本和重新配置的投资等等。这些成本的综合往往会超过购买一套基于硬件的RAID解决方 案所需投资。 这里www.CTOHome.com简单总结如下：软件raid和硬件raid的区别：硬件raid性能完胜软件raid，因为硬件raid里面有cpu缓存，电池等设备来做raid的读写操作。而软件raid则是依赖操作系统的软件来做这些事情。软件raid要消耗较多的cpu和内存资源。raid0，raid1，raid10 用软件raid来做还是过得去的，但是raid5等，就推荐硬件raid了。

    一些raid的知识

    • Linear mode
      • Two or more disks are combined into one physical device. The disks are "appended" to each other, so writing linearly to the RAID device will fill up disk 0 first, then disk 1 and so on. The disks does not have to be of the same size. In fact, size doesn't matter at all here :)
      • There is no redundancy in this level. If one disk crashes you will most probably lose all your data. You can however be lucky to recover some data, since the filesystem will just be missing one large consecutive chunk of data.
      • The read and write performance will not increase for single reads/writes. But if several users use the device, you may be lucky that one user effectively is using the first disk, and the other user is accessing files which happen to reside on the second disk. If that happens, you will see a performance gain.
    • RAID-0 读写性能最好，安全性最差，容量=硬盘之和
      • Also called "stripe" mode. The devices should (but need not) have the same size. Operations on the array will be split on the devices; for example, a large write could be split up as 4 kB to disk 0, 4 kB to disk 1, 4 kB to disk 2, then 4 kB to disk 0 again, and so on. If one device is much larger than the other devices, that extra space is still utilized in the RAID device, but you will be accessing this larger disk alone, during writes in the high end of your RAID device. This of course hurts performance.
      • Like linear, there is no redundancy in this level either. Unlike linear mode, you will not be able to rescue any data if a drive fails. If you remove a drive from a RAID-0 set, the RAID device will not just miss one consecutive block of data, it will be filled with small holes all over the device. e2fsck or other filesystem recovery tools will probably not be able to recover much from such a device.
      • The read and write performance will increase, because reads and writes are done in parallel on the devices. This is usually the main reason for running RAID-0. If the busses to the disks are fast enough, you can get very close to N*P MB/sec.
    • RAID-1  读性能不错，写性能差。安全性好。容量=硬盘的50%
      • This is the first mode which actually has redundancy. RAID-1 can be used on two or more disks with zero or more spare-disks. This mode maintains an exact mirror of the information on one disk on the other disk(s). Of Course, the disks must be of equal size. If one disk is larger than another, your RAID device will be the size of the smallest disk.
      • If up to N-1 disks are removed (or crashes), all data are still intact. If there are spare disks available, and if the system (eg. SCSI drivers or IDE chipset etc.) survived the crash, reconstruction of the mirror will immediately begin on one of the spare disks, after detection of the drive fault.
      • Write performance is often worse than on a single device, because identical copies of the data written must be sent to every disk in the array. With large RAID-1 arrays this can be a real problem, as you may saturate the PCI bus with these extra copies. This is in fact one of the very few places where Hardware RAID solutions can have an edge over Software solutions - if you use a hardware RAID card, the extra write copies of the data will not have to go over the PCI bus, since it is the RAID controller that will generate the extra copy. Read performance is good, especially if you have multiple readers or seek-intensive workloads. The RAID code employs a rather good read-balancing algorithm, that will simply let the disk whose heads are closest to the wanted disk position perform the read operation. Since seek operations are relatively expensive on modern disks (a seek time of 6 ms equals a read of 123 kB at 20 MB/sec), picking the disk that will have the shortest seek time does actually give a noticeable performance improvement.
    • RAID-4
      • This RAID level is not used very often. It can be used on three or more disks. Instead of completely mirroring the information, it keeps parity information on one drive, and writes data to the other disks in a RAID-0 like way. Because one disk is reserved for parity information, the size of the array will be (N-1)*S, where S is the size of the smallest drive in the array. As in RAID-1, the disks should either be of equal size, or you will just have to accept that the S in the (N-1)*S formula above will be the size of the smallest drive in the array.
      • If one drive fails, the parity information can be used to reconstruct all data. If two drives fail, all data is lost.
      • The reason this level is not more frequently used, is because the parity information is kept on one drive. This information must be updated every time one of the other disks are written to. Thus, the parity disk will become a bottleneck, if it is not a lot faster than the other disks. However, if you just happen to have a lot of slow disks and a very fast one, this RAID level can be very useful.
    • RAID-5
      • This is perhaps the most useful RAID mode when one wishes to combine a larger number of physical disks, and still maintain some redundancy. RAID-5 can be used on three or more disks, with zero or more spare-disks. The resulting RAID-5 device size will be (N-1)*S, just like RAID-4. The big difference between RAID-5 and -4 is, that the parity information is distributed evenly among the participating drives, avoiding the bottleneck problem in RAID-4.
      • If one of the disks fail, all data are still intact, thanks to the parity information. If spare disks are available, reconstruction will begin immediately after the device failure. If two disks fail simultaneously, all data are lost. RAID-5 can survive one disk failure, but not two or more.
      • Both read and write performance usually increase, but can be hard to predict how much. Reads are similar to RAID-0 reads, writes can be either rather expensive (requiring read-in prior to write, in order to be able to calculate the correct parity information), or similar to RAID-1 writes. The write efficiency depends heavily on the amount of memory in the machine, and the usage pattern of the array. Heavily scattered writes are bound to be more expensive.

  • 点这里复制本页地址发送给您QQ/MSN上的好友