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¸¦ ¾×¼¼½ºÇϸç
±× 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.

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Level 0
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Level 1
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Level 5
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Level 0 + 1
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ÀåÁ¡
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- DISK I/O°¡ ºÐ»êÀÌ µÈ´Ù.
- RAID levelÁß °¡Àå ºü¸£´Ù.
- DATA ÀúÀå È¿À²ÀÌ ³ô´Ù.
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- ¾ÈÁ¤ÀûÀÌ´Ù.
- redundantÇØ¼ Fault Tolerance¸¦ º¸ÀåÇÑ´Ù.
- simultaneous-read°¡ µÇ±â ¶§¹®¿¡ ±âÁ¸ÀÇ ¹æ¹ý¿¡ 2¹èÁ¤µµ Àбâ
È¿°ú¸¦ ÁØ´Ù.
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- 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.
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- Level 0°ú Level 1ÀÇ ÀåÁ¡À» °¡Áø´Ù.
¡¡
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´ÜÁ¡
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- Fault Tolerance°¡ º¸ÀåµÇÁö ¾Ê´Â´Ù.
- ¾ÈÁ¤ÀûÀÌÁö ¸øÇÏ´Ù.
- redundant°¡ ¾ø´Ù.
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- ºñ¿ëÀÌ ºñ½Î´Ù.
- StripingÀÌ µÇÁö¸¦ ¾Ê±â ¶§¹®¿¡ disk I/O bottleneck Çö»ó¿¡
´ëÇØ È¿À²ÀûÀÌÁö ¸øÇÏ´Ù.
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- level 1¿¡ ºñÇØ¼ Àб⠼º´ÉÀÌ ¶³¾îÁø´Ù.
- level 0¿¡ ºñÇØ ÀúÀåÈ¿À²ÀÌ ¶³¾îÁø´Ù.
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- ºñ¿ëÀÌ ºñ½Î´Ù.
- disk ÀúÀå È¿À²¼ºÀÌ ±×¸® ³ôÁö ¾Ê´Ù.
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