(±â»çµî·ÏÀÏ : 2001-07-30 19:12:52)

 

RAID 0

RAID-0´Â ÀüÇüÀûÀÎ Parity°¡ ¾ø´Â striped disk driveµéÀÇ non-redundant groupÀ¸·Î Á¤ÀǵȴÙ. RAID-0 array´Â º¸Åë I/O intensive applicationÀ» À§ÇÑ large stripes·Î ±¸¼ºµÇ´Âµ¥, Á¾Á¾ data intensive applicationÀÇ single-user¸¦ À§ÇÑ synchronized spindle driveµéÀ» ÀÌ¿ëÇÑ sector-stripeÀ¸·Î ±¸¼ºÇÒ ¼öµµÀÖ´Ù.

RAID-0´Â redundancy¸¦ Áö¿øÇÏÁö ¾Ê±â ¶§¹®¿¡ ¸¸ÀÏ Array³»ÀÇ ÇϳªÀÇ drive°¡ Àå¾Ö¸¦ ÀÏÀ¸Å°¸é, Array Àüü°¡ Àå¾Ö¸¦ ÀÏÀ¸Å°°Ô µÈ´Ù. ±×·¯³ª RAID-0´Â ¸ðµç Array typeÁß °¡Àå ºü¸£°í dataÀúÀå È¿À²ÀÌ ³ô´Ù.

RAID 1

Disk MirroringÀ̶ó ºÒ¸®´Â RAID-1Àº data¸¦ Áߺ¹ ÀúÀåÇϵµ·Ï µð½ºÅ©µå¶óÀ̺êµéÀ» ½Ö·Î ±¸¼ºÇÑ °ÍÀ¸·Î ¼­¹öÂÊÀ¸·Î´Â ÇϳªÀÇ µå¶óÀ̺ê·Î ÀνĵȴÙ. RAID-1Àº stripingÀº »ç¿ëµÇÁö ¾Ê´Â ¹Ý¸é, ¿©·¯°³ÀÇ RAID-1 arrayµéÀÌ ¼­·Î stripedµÇ¾î mirrored drives pairµé·Î ±¸¼ºµÈ ÇϳªÀÇ ´ë¿ë·® array·Î ±¸¼º ½Ãų ¼ö ÀÖÀ¸¸ç, À̸¦ "Dual-level array" ¶Ç´Â RAID-10À̶ó ºÎ¸¥´Ù.

Write´Â Mirrored PairÀÎ µÎ°³ÀÇ Drive¿¡ µ¿½Ã¿¡ ÀúÀåµÇ¾î °¢ Drive°¡ µ¿ÀÏÇÑ Á¤º¸¸¦ ÀúÀåÇÏ°Ô µÈ´Ù. ±×·¯³ª °¢ Drive´Â Simultaneous Read OperationÀ» ¼öÇàÇÒ ¼ö ÀÖ´Ù. µû¶ó¼­, °¢ DriveÀÇ Read Performance´Â µÎ¹è·Î µÇ°í Write Performance´Â º¯È­°¡ ¾ø°Ô µÈ´Ù. RAID-1Àº Redundant¸¦ °¡Áø ArrayÁß¿¡¼­´Â ÃÖ°íÀÇ Performance¸¦ º¸À̸ç, ƯÈ÷ Multi-user Environment¿¡¼­ À¯¿ëÇÏ´Ù.

RAID 3

RAID-3´Â RAID-2ó·³ Sector-striped data¸¦ Drive Group¿¡ °ÉÃÄ ÀúÀåÇÏÁö¸¸, Group³»ÀÇ ÇϳªÀÇ Drive´Â Parity Information¸¸À» ÀúÀåÇϵµ·Ï ÁöÁ¤µÈ´Ù. RAID-3´Â Error DetectionÀ» À§Çؼ­´Â °¢ sector¿¡ embbedµÈ ECC¿¡ ÀÇÁ¸ÇÑ´Ù.

Hard Drive°¡ Àå¾Ö¸¦ ÀÏÀ¸Å³ °æ¿ì, Data º¹±¸´Â ³²¾ÆÀÖ´Â Drive»ó¿¡ ±â·ÏµÈInformationÀÇ Exclusive OR(XOR)¿¬»êÀ» ÅëÇÏ¿© ÀÌ·ç¾îÁø´Ù.

Records´Â ÀüÇüÀûÀ¸·Î ¸ðµç Drive¿¡ °ÉÃÄ Àֱ⶧¹®¿¡, Data Intensive ȯ°æ¿¡ ÀûÇÕÇÏ´Ù. °¢ I/OÀº Array³»ÀÇ ¸ðµç DriveµéÀ» ¾×¼¼½ºÇϱ⠶§¹®¿¡, RAID-3 Array´Â I/OÀ» Overlap½Ãų ¼ö°¡ ¾ø°í µû¶ó¼­, RAID-3´Â long recordÀÇ Single-user, Single-tasking ȯ°æ¿¡ ÀûÇÕÇÏ´Ù. ±×·¯¹Ç·Î Short record¿¡¼­ÀÇ ¼º´É ÀúÇϸ¦ ÇÇÇϱâ À§Çؼ­´Â, RAID-3´Â Synchronized-spindle drives°¡ ÇÊ¿äÇÏ´Ù.

RAID 5

Á¾Á¾ Rotating Parity Array¶ó ºÒ¸®´Â RAID-5´Â RAID-4¿¡¼­ ÇϳªÀÇ Àü¿ëParity Drive¸¦ ¼³Á¤ÇÔÀ¸·Î½á, Parity Update°¡ ÇÑ Drive¿¡¼­ ÀÌ·ç¾îÁö¹Ç·Î »ý±â´Â Write BottleneckÀ» ÇÇÇϱâ À§ÇÏ¿© ¸¸µé¾îÁø RAID ArrayÀÌ´Ù.

RAID-5´Â RAID-4ó·³ large-stripeÀÌ »ç¿ëµÇ¾î multiple I/O operationÀÌ overlapµÇµµ·Ï Çϰí ÀÖ´Ù. ±×·¯³ª, RAID-4¿Í´Â ´Ù¸£°Ô, °¢ DriveµéÀÌ ÀÏ·ÃÀÇ ¼­·Î´Ù¸¥ stripesµé¿¡ ´ëÇÑ parity¸¦ µ¹¾Æ°¡¸é¼­ ÀúÀåÇÏ°Ô µÈ´Ù.

µû¶ó¼­, Àü¿ë parity Drive°¡ ¾ø±â ¶§¹®¿¡ ¸ðµç driveµéÀÌ µ¥ÀÌŸ¸¦ ÀúÀåÇÒ ¼ö ÀÖ°í, Read operationÀÌ ¸ðµç drive¿¡ °ÉÃÄ overlapµÉ ¼ö ÀÖ´Ù.Write OperationÀº ÀüÇüÀûÀ¸·Î single data drive¸¦ ¾×¼¼½ºÇÏ¸ç ±× record¿¡ ´ëÇÑ parity drive¸¦ ¾×¼¼½ºÇÑ´Ù.

µû¶ó¼­, RAID-4¿Í´Â ´Þ¸® ¼­·Î ´Ù¸¥ recordsµéÀÌ ÇØ´ç parityµéÀ» ¼­·Î ´Ù¸¥ driveµé¿¡ ÀúÀåÇϱ⠶§¹®¿¡, Write Operationµµ overlapÀÌ °¡´ÉÇÏ´Ù. RAID-5´Â RAID-1ÀÌ ¸ðµç µ¥ÀÌŸ¸¦ redundant copyÇÏ´Â °Í°ú´Â ´Þ¸®, parity information¸¸À» ÀúÀåÇϱ⠶§¹®¿¡ RAID-1¿¡ ºñÇÏ¿© Storage Efficiency¸¦ ³ôÀÏ ¼ö ÀÖ´Ù. °á°úÀûÀ¸·Î RAID-5 Array´Â ¾î¶² ¼öÀÇ Driveµµ ¿¬°áÀÌ °¡´ÉÇϰí, °¢ DriveµéÀº Parity information ÀúÀå ºÎºÐ¸¸À» Á¦¿ÜÇϰí´Â ¸ðµÎ data storage·Î Ȱ¿ëµÉ ¼ö ÀÖ´Ù. Áï, RAID-5´Â RAID-1º¸´Ù ÀúÀå ÀåÄ¡¸¦ È¿À²ÀûÀ¸·Î ±Ø´ëÈ­ ½Ãų ¼ö ÀÖ´Ù. ±×·¯³ª performance¿¡¼­´Â ¼Õ½ÇÀ» °¨¼ö ÇÏ¿©¾ß ÇÑ´Ù.

Data°¡ RAID-5 Array¿¡ ¾²¿©Áú ¶§, Parity information ¶ÇÇÑ UpdateµÇ¾î¾ß Çϴµ¥, ÀÌ´Â Write Operation¿¡ ÀÇÇÏ¿© ¾î¶² data bitµéÀÌ ¹Ù²î¾ú´ÂÁö¸¦ ã¾Æ³»¾î ÀÌ¿¡ ÇØ´çÇÏ´Â parity bitsµéÀ» ¹Ù²Ù¹Ç·Î¼­ UpdateµÈ´Ù.

ÀÌ´Â overwrittenµÉ old data¸¦ ¸ÕÀú Àаí, ÀÌ °ÍÀÌ »õ·Î overwriteµÉ »õ·Î¿î µ¥ÀÌŸ¿Í XOR ¿¬»êÀ» ÇÏ¹Ç·Î½á ¼öÇàµÈ´Ù. ÀÌ °ÍÀº ¹Ù²ï ¸ðµç bitÀÇ position¿¡¼­ 1ÀÌ µÇ´Â bit mask¸¦ ¸¸µé°Ô µÇ°í, ÀÌ bit mask°¡ parity drive·Î ºÎÅÍÀÐ¾î µéÀÎ old parity information°ú XOR¿¬»êÀ» ¼öÇàÇÑ´Ù. ÀÌ °á°ú, Parity information³»¿¡ ÀÖ´Â ÇØ´ç bit¸¦ º¯È­ ½ÃŲ´Ù. ÀÌ·¸°Ô ÇÏ¿© UpdateµÈ Parity´Â Parity Drive¿¡ write backµÈ´Ù.

±×·¯¹Ç·Î, write-requestÇÏ´Â ¸ðµç Application¿¡ ´ëÇÏ¿© RAID-5 Array´Â µÎ°³ ÀÇ Read, µÎ°³ÀÇ Write¿Í µÎ°³ÀÇ XOR operationÀ» ¼öÇàÇÏ¿©¾ß ¸¸ÀÌ ¿ø·¡ÀÇ write°¡ ¿Ï·áµÈ´Ù.

RAID-1¿¡¼­ÀÇ redundant data¿¡ ºñÇÏ¿©, Parity¸¦ ÀúÀåÇÏ´Â RAID-5´Â À§¿Í °°ÀÌ º¸´Ù ¸¹Àº ¿¬»êÀ» ÇàÇÏ°Ô µÇ¸ç, write operation Áß¿¡ parity informationÀ» Àç»ýÇϴµ¥ Ãß°¡ÀûÀ¸·Î ½Ã°£ÀÌ ¼Ò¿äµÈ´Ù. ÀÌ·¯ÇÑ ÀÌÀ¯ ¶§¹®¿¡ RAID-5´Â RAID-1¿¡ ºñÇÏ¿© write performance°¡ ¾à 3/5~1/3 ¼öÁعۿ¡ µÇÁö ¾Ê´Â´Ù. À̶§¹®¿¡, RAID-5 Array´Â °áÄÚ SoftwareÀûÀ¸·Î »ç¿ëµÇÁö ¾ÊÀ¸¸ç, ¾Æ¿ï·¯ µðÁöÅ» ºñµð¿À ĸÃÄ¿Í °°ÀÌ write performance°¡ Áß¿äÇÑ Application¿¡´Â »ç¿ëµÇÁö ¾Ê´Â´Ù.

 

Level 0

Level 1

Level 5

Level 0 + 1

ÀåÁ¡

- DISK I/O°¡ ºÐ»êÀÌ µÈ´Ù.
- RAID levelÁß °¡Àå ºü¸£´Ù.
- DATA ÀúÀå È¿À²ÀÌ ³ô´Ù.

- ¾ÈÁ¤ÀûÀÌ´Ù.
- redundantÇØ¼­ Fault Tolerance¸¦ º¸ÀåÇÑ´Ù.
- simultaneous-read°¡ µÇ±â ¶§¹®¿¡ ±âÁ¸ÀÇ ¹æ¹ý¿¡ 2¹èÁ¤µµ Àбâ È¿°ú¸¦ ÁØ´Ù.

- Write-bottleneck Çö»óÀ» ÁÙÀÏ ¼ö ÀÖ´Ù.
- ¾ÈÁ¤ÀûÀÌ´Ù.
- disk I/O¸¦ ÁÙÀÏ ¼ö ÀÖ´Ù.
- hot-swap, hot-fix, hot-spare, hot-plugµîÀÌ °¡´ÉÇÏ´Ù.

- Level 0°ú Level 1ÀÇ ÀåÁ¡À» °¡Áø´Ù.

¡¡

´ÜÁ¡

- Fault Tolerance°¡ º¸ÀåµÇÁö ¾Ê´Â´Ù.
- ¾ÈÁ¤ÀûÀÌÁö ¸øÇÏ´Ù.
- redundant°¡ ¾ø´Ù.

- ºñ¿ëÀÌ ºñ½Î´Ù.
- StripingÀÌ µÇÁö¸¦ ¾Ê±â ¶§¹®¿¡ disk I/O bottleneck Çö»ó¿¡ ´ëÇØ È¿À²ÀûÀÌÁö ¸øÇÏ´Ù.

- level 1¿¡ ºñÇØ¼­ Àб⠼º´ÉÀÌ ¶³¾îÁø´Ù.
- level 0¿¡ ºñÇØ ÀúÀåÈ¿À²ÀÌ ¶³¾îÁø´Ù.

- ºñ¿ëÀÌ ºñ½Î´Ù.
- disk ÀúÀå È¿À²¼ºÀÌ ±×¸® ³ôÁö ¾Ê´Ù.



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