2.3.2. 条​​​​​​​状​​​​​​​逻​​​​​​​辑​​​​​​​卷​​​​​​​

当​​​​​​​您​​​​​​​向​​​​​​​ LVM 逻​​​​​​​辑​​​​​​​卷​​​​​​​写​​​​​​​入​​​​​​​数​​​​​​​据​​​​​​​时​​​​​​​,文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​在​​​​​​​基​​​​​​​本​​​​​​​物​​​​​​​理​​​​​​​卷​​​​​​​之​​​​​​​间​​​​​​​部​​​​​​​署​​​​​​​数​​​​​​​据​​​​​​​。​​​​​​​您​​​​​​​可​​​​​​​以​​​​​​​通​​​​​​​过​​​​​​​创​​​​​​​建​​​​​​​条​​​​​​​状​​​​​​​逻​​​​​​​辑​​​​​​​卷​​​​​​​控​​​​​​​制​​​​​​​数​​​​​​​据​​​​​​​向​​​​​​​物​​​​​​​理​​​​​​​卷​​​​​​​写​​​​​​​入​​​​​​​的​​​​​​​方​​​​​​​法​​​​​​​。​​​​​​​对​​​​​​​于​​​​​​​大​​​​​​​批​​​​​​​量​​​​​​​的​​​​​​​读​​​​​​​取​​​​​​​和​​​​​​​写​​​​​​​入​​​​​​​,这​​​​​​​样​​​​​​​可​​​​​​​以​​​​​​​提​​​​​​​高​​​​​​​数​​​​​​​据​​​​​​​输​​​​​​​入​​​​​​​/输​​​​​​​出​​​​​​​的​​​​​​​效​​​​​​​率​​​​​​​。​​​​​​​
条​​​​​​​带​​​​​​​化​​​​​​​数​​​​​​​据​​​​​​​可​​​​​​​通​​​​​​​过​​​​​​​以​​​​​​​ round-round 模​​​​​​​式​​​​​​​向​​​​​​​预​​​​​​​定​​​​​​​数​​​​​​​目​​​​​​​的​​​​​​​物​​​​​​​理​​​​​​​卷​​​​​​​写​​​​​​​入​​​​​​​数​​​​​​​据​​​​​​​来​​​​​​​提​​​​​​​高​​​​​​​性​​​​​​​能​​​​​​​。​​​​​​​使​​​​​​​用​​​​​​​条​​​​​​​带​​​​​​​模​​​​​​​式​​​​​​​,I/O 可​​​​​​​以​​​​​​​平​​​​​​​行​​​​​​​执​​​​​​​行​​​​​​​。​​​​​​​在​​​​​​​有​​​​​​​些​​​​​​​情​​​​​​​况​​​​​​​下​​​​​​​,这​​​​​​​样​​​​​​​可​​​​​​​以​​​​​​​使​​​​​​​条​​​​​​​带​​​​​​​中​​​​​​​每​​​​​​​个​​​​​​​附​​​​​​​加​​​​​​​的​​​​​​​物​​​​​​​理​​​​​​​卷​​​​​​​获​​​​​​​得​​​​​​​类​​​​​​​似​​​​​​​线​​​​​​​性​​​​​​​卷​​​​​​​的​​​​​​​性​​​​​​​能​​​​​​​。​​​​​​​
以​​​​​​​下​​​​​​​示​​​​​​​例​​​​​​​显​​​​​​​示​​​​​​​数​​​​​​​据​​​​​​​在​​​​​​​三​​​​​​​个​​​​​​​物​​​​​​​理​​​​​​​卷​​​​​​​之​​​​​​​间​​​​​​​进​​​​​​​行​​​​​​​条​​​​​​​状​​​​​​​分​​​​​​​布​​​​​​​。​​​​​​​在​​​​​​​这​​​​​​​个​​​​​​​图​​​​​​​表​​​​​​​中​​​​​​​:
  • 数​​​​​​​据​​​​​​​的​​​​​​​第​​​​​​​一​​​​​​​条​​​​​​​写​​​​​​​入​​​​​​​ PV1
  • 数​​​​​​​据​​​​​​​的​​​​​​​第​​​​​​​二​​​​​​​条​​​​​​​写​​​​​​​入​​​​​​​ PV2
  • 数​​​​​​​据​​​​​​​的​​​​​​​第​​​​​​​三​​​​​​​条​​​​​​​写​​​​​​​入​​​​​​​ PV3
  • 数​​​​​​​据​​​​​​​的​​​​​​​第​​​​​​​四​​​​​​​条​​​​​​​写​​​​​​​入​​​​​​​ PV1
在​​​​​​​条​​​​​​​状​​​​​​​逻​​​​​​​辑​​​​​​​卷​​​​​​​中​​​​​​​,条​​​​​​​的​​​​​​​大​​​​​​​小​​​​​​​不​​​​​​​能​​​​​​​超​​​​​​​过​​​​​​​扩​​​​​​​展​​​​​​​的​​​​​​​大​​​​​​​小​​​​​​​。​​​​​​​
在​​​​​​​三​​​​​​​个​​​​​​​ PV 中​​​​​​​条​​​​​​​状​​​​​​​分​​​​​​​配​​​​​​​数​​​​​​​据​​​​​​​

图 2.5. 在​​​​​​​三​​​​​​​个​​​​​​​ PV 中​​​​​​​条​​​​​​​状​​​​​​​分​​​​​​​配​​​​​​​数​​​​​​​据​​​​​​​

Striped logical volumes can be extended by concatenating another set of devices onto the end of the first set. In order extend a striped logical volume, however, there must be enough free space on the underlying physical volumes that make up the volume group to support the stripe. For example, if you have a two-way stripe that uses up an entire volume group, adding a single physical volume to the volume group will not enable you to extend the stripe. Instead, you must add at least two physical volumes to the volume group. For more information on extending a striped volume, see 第 4.4.9 节 “扩​​​​​​​展​​​​​​​条​​​​​​​状​​​​​​​卷​​​​​​​”.