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Преимущества и недостатки ZFS

Написано: 2018-06-23.

ZFS кардинально отличается от всех существующих "классических" файловых систем. Об её устройстве можно писать целые книги. Здесь я попытался привести очень краткий список фактов об этой ФС.

Какие преимущества она имеет для простого пользователя дома или на работе?

А что она даст пользователям более серьёзных и крупных систем, в дополнение к предыдущему списку?

Но ведь должны быть недостатки? Безусловно!

Не смотря на все эти недостатки и дороговизну, даже домашнему пользователю преимущества удобства работы, создания бэкапов и мгновенных снимков, контроль целостности данных должны перевесить.

Для удобства прикидывания конфигураций массивов (производительность чтения/записи, IOPS чтения/записи, полезного места), привожу таблицу из FreeBSD Mastery: ZFS книги.

+-------------------------------------------------------------------------------------------+
|Disks|Config| ReadIOPS | WriteIOPS | ReadMB/s | WriteMB/s | Usable Space | Fault Tolerance |
|-----+------+----------+-----------+----------+-----------+--------------+-----------------|
|1    |Stripe| 250      | 250       | 100      | 100       | 1 TB (100%)  | none            |
+-------------------------------------------------------------------------------------------+

+-------------------------------------------------------------------------------------------+
|Disks|Config           |ReadIOPS|WriteIOPS|ReadMB/s|WriteMB/s|Usable Space|Fault Tolerance |
|-----+-----------------+--------+---------+--------+---------+------------+----------------|
|2    |2 x Stripe       |500     |500      |200     |200      |2 TB (100%) |none            |
|-----+-----------------+--------+---------+--------+---------+------------+----------------|
|2    |1 x 2 disk Mirror|500     |250      |200     |100      |1 TB (50%)  |1               |
+-------------------------------------------------------------------------------------------+

+-------------------------------------------------------------------------------------------+
|Disks|Config            |ReadIOPS|WriteIOPS|ReadMB/s|WriteMB/s|Usable Space|Fault Tolerance|
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|3    |1 x 3 disk Mirror |750     |250      |300     |100      |1 TB (33%)  |2              |
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|3    |1 x 3 disk RAID-Z1|250     |250      |200     |200      |2 TB (66%)  |1              |
+-------------------------------------------------------------------------------------------+

+-------------------------------------------------------------------------------------------+
|Disks|Config            |ReadIOPS|WriteIOPS|ReadMB/s|WriteMB/s|Usable Space|Fault Tolerance|
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|4    |2 x 2 disk Mirror |1000    |500      |400     |200      |2 TB (50%)  |2 (1/VDEV)     |
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|4    |1 x 4 disk RAID-Z1|250     |250      |300     |300      |3 TB (75%)  |1              |
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|4    |1 x 4 disk RAID-Z2|250     |250      |200     |200      |2 TB (50%)  |2              |
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|5    |1 x 5 disk RAID-Z1|250     |250      |400     |400      |4 TB (80%)  |1              |
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|5    |1 x 5 disk RAID-Z2|250     |250      |300     |300      |3 TB (60%)  |2              |
|-----+------------------+--------+---------+--------+---------+------------+---------------|
|5    |1 x 5 disk RAID-Z3|250     |250      |200     |200      |2 TB (40%)  |3              |
+-------------------------------------------------------------------------------------------+

+--------------------------------------------------------------------------------------------+
|Disks|Config             |ReadIOPS|WriteIOPS|ReadMB/s|WriteMB/s|Usable Space|Fault Tolerance|
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|6    |3 x 2 disk Mirror  |1500    |750      |600     |300      |3 TB (50%)  |3 (1/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|6    |2 x 3 disk Mirror  |1500    |500      |600     |200      |2 TB (33%)  |4 (2/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|6    |1 x 6 disk RAID-Z1 |250     |250      |500     |500      |5 TB (83%)  |1              |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|6    |1 x 6 disk RAID-Z2 |250     |250      |400     |400      |4 TB (66%)  |2              |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|6    |1 x 6 disk RAID-Z3 |250     |250      |300     |300      |3 TB (50%)  |3              |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |6 x 2 disk Mirror  |3000    |1500     |1200    |600      |6 TB (50%)  |6 (1/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |4 x 3 disk Mirror  |3000    |1000     |1200    |400      |4 TB (33%)  |8 (2/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |1 x 12 disk RAID-Z1|250     |250      |1100    |1100     |11 TB (92%) |1              |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |2 x 6 disk RAID-Z1 |500     |500      |1000    |1000     |10 TB (83%) |2 (1/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |3 x 4 disk RAID-Z1 |750     |750      |900     |900      |9 TB (75%)  |3 (1/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |1 x 12-disk RAID-Z2|250     |250      |1000    |1000     |10 TB (83%) |2              |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |2 x 6-disk RAID-Z2 |500     |500      |800     |800      |8 TB (66%)  |4 (2/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |1 x 12-disk RAID-Z3|250     |250      |900     |900      |9 TB (75%)  |3              |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|12   |2 x 6-disk RAID-Z3 |500     |500      |600     |600      |6TB (50%)   |6 (3/VDEV)     |
+--------------------------------------------------------------------------------------------+

+--------------------------------------------------------------------------------------------+
|Disks|Config             |ReadIOPS|WriteIOPS|ReadMB/s|WriteMB/s|Usable Space|Fault Tolerance|
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|36   |18 x 2 disk Mirror |9000    |4500     |3600    |1800     |18 TB (50%) |18 (1/VDEV)    |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|36   |12 x 3 disk Mirror |9000    |3000     |3600    |1200     |12 TB (33%) |24 (2/VDEV)    |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|36   |1 x 36 disk RAID-Z2|250     |250      |3400    |3400     |34 TB (94%) |2              |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|36   |2 x 18 disk RAID-Z2|500     |500      |3200    |3200     |32 TB (89%) |4 (2/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|36   |4 x 9 disk RAID-Z2 |1000    |1000     |2800    |2800     |28 TB (78%) |8 (2/VDEV)     |
|-----+-------------------+--------+---------+--------+---------+------------+---------------|
|36   |6 x 6 disk RAID-Z2 |1500    |1500     |2400    |2400     |24 TB (66%) |12 (2/VDEV)    |
+--------------------------------------------------------------------------------------------+

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