Calculate usable RAID capacity, parity or mirror overhead and how many drive failures RAID 0, 1, 5, 6 and 10 survive, in TB and the TiB Windows shows.
புதுப்பிக்கப்பட்டது சரிபார்க்கப்பட்ட எடுத்துக்காட்டுகள்: 6
RAID 5 on 4 drives of 8 TB gives 24 TB usable (21.83 TiB in the binary units Windows shows), 75% of the raw space, and always survives 1 failed drive.
Drive labels use 1 TB = 10¹² bytes. Windows divides by 2⁴⁰ but still prints “TB”, so a new drive looks about 9% smaller there; macOS reports decimal TB.
One drive's worth of parity is spread across all drives. Every member counts as the smallest drive in the set.
1 drive
Usable capacity is the drive size times the number of drives' worth of space that holds data: n for RAID 0 striping, 1 for a RAID 1 mirror, n − 1 for RAID 5 single parity, n − 2 for RAID 6 double parity and n ÷ 2 for RAID 10 striped mirrors. The rest of the raw space holds copies or parity, which is what lets the array keep running after a drive fails.
People use it to size a NAS or server before buying drives. The default, four 8 TB drives in RAID 5, gives 24 TB usable out of 32 TB raw, 75% efficiency, and survives one failed drive. In Windows the same space appears as 21.83 TB, because Windows divides by 2^40 (the binary TiB) but prints "TB".
The results assume identical drives; with mixed sizes, each drive counts as the smallest one. File-system metadata, hot spares and reserved space are not subtracted, so the room left for files is slightly lower.
சரிபார்ப்பின் மூலம்: Python 3.8 decimal: (4 − 1) × 8 = 24 TB; 24e12 / 2**40 = 21.8279 TiB; 8e12 / 2**40 = 7.2760 TiB
சரிபார்ப்பின் மூலம்: Python 3.8: (6 − 2) × 4 = 16; 16/24 = 66.67%
சரிபார்ப்பின் மூலம்: Python 3.8: 4 / 2 × 2 = 4 TB; with 2 mirror pairs one failure per pair is survivable, but two in the same pair are not
சரிபார்ப்பின் மூலம்: Definition: every member holds a full copy
RAID 5 gives (n − 1) × drive size, because one drive's worth of space holds parity. Four 8 TB drives give 24 TB (75%) and eight give 56 TB (87.5%). It needs at least 3 drives and survives exactly one failure. Efficiency rises as you add drives, but so does the amount of data a rebuild must read without hitting a second failure.
RAID 6 stores two independent parities (P and Q) instead of one, so it survives any 2 failed drives at the cost of a second drive's capacity. With six 4 TB drives, RAID 5 gives 20 TB and RAID 6 gives 16 TB. A small random write costs 4 disk I/Os on RAID 5 and 6 on RAID 6, so RAID 6 writes are slower.
RAID 10 is faster and rebuilds more safely, while RAID 5 stores more. RAID 10 always keeps 50% of raw space, so 4 × 8 TB gives 16 TB against 24 TB for RAID 5. A small random write costs 2 disk I/Os instead of 4, and a rebuild copies one mirror partner instead of reading every drive. RAID 10 survives 1 failure for certain and up to half its drives if each is in a different pair.
Drive makers use decimal units, 1 TB = 10^12 bytes, while Windows divides by 2^40 = 1,099,511,627,776 bytes and still labels the result TB. 8 × 10^12 ÷ 2^40 = 7.28, so no space is missing; the gap is about 9% at terabyte scale. IEC 80000-13 names the binary unit the tebibyte (TiB). Macs have reported decimal units since OS X Snow Leopard.
No. RAID keeps an array running through drive failures, but deletions, ransomware encryption and file-system corruption reach every drive at once, and RAID 0 has no redundancy at all. Keep separate backups: CISA recommends the 3-2-1 rule, which means 3 copies of important files, on 2 different media types, with 1 copy stored off-site.
துல்லியம் உங்கள் உள்ளீடுகளையும் முறையின் அனுமானங்களையும் சார்ந்தது. தசமக் கணக்கீடு 50 முக்கிய இலக்கங்களைப் பயன்படுத்துகிறது. ஆனால் மதிப்பீடுகள், எண் முறைகள், மூலத் தரவுகள் குறைந்த துல்லியத்தைக் கொண்டிருக்கலாம்; காட்டப்படும் மதிப்பை வட்டமிடுவது இந்த வரம்புகளை நீக்காது. சுயாதீன மூலங்களின் தீர்வுகளுடன் சரிபார்க்கப்பட்ட எடுத்துக்காட்டுகள்: 6. எடுத்துக்காட்டாக, “RAID 5 with 4 × 8 TB” என்பது Python 3.8 decimal: (4 − 1) × 8 = 24 TB; 24e12 / 2**40 = 21.8279 TiB; 8e12 / 2**40 = 7.2760 TiB உடன் சரிபார்க்கப்படுகிறது.
SNIA Common RAID Disk Data Format (DDF) Specification, rev. 2.0 — RAID level definitions; Patterson, Gibson & Katz (1988), A Case for Redundant Arrays of Inexpensive Disks (RAID), SIGMOD; IEC 80000-13:2008 — binary prefixes (1 TiB = 2⁴⁰ bytes).
இந்தக் கணிப்பானில் சுயாதீன ஆதாரங்களிலிருந்து பதில்கள் பெறப்பட்ட 6 தீர்க்கப்பட்ட எடுத்துக்காட்டுகள் உள்ளன. இவை சோதனைத் தொகுப்பில் இயங்குகின்றன; இங்கேயும் அவற்றை இயக்கலாம்.
Download or upload time for a file at a given speed, the data a link moves in a set time, and a website's monthly bandwidth from page views.
Find the network address, broadcast, usable host range and host count of any IPv4 or IPv6 CIDR block, with netmask, wildcard and equal subnets.
Operation counts and running times for O(1), O(log n), O(n), O(n log n), O(n²), O(n³), O(2ⁿ) and O(n!) at your input size, on a log-scale chart.