Почему мой магнитофон такой медленный?

Question

Я купил использованный стример Quantum Ultrium LTO-4 и подключил его к контроллеру HP Smart Array P400 SAS в моем HP ProLiant N54l. Я использую FreeBSD 11 в качестве операционной системы.

Теперь я вставил ленту и провел тест команды Bacula btape :

$ btape /dev/nsa0
Tape block granularity is 1024 bytes.
btape: butil.c:291-0 Using device: "/dev/nsa0" for writing.
btape: btape.c:471-0 open device "LTO-4" (/dev/nsa0): OK
*rewind
btape: btape.c:576-0 Rewound "LTO-4" (/dev/nsa0)
*speed
btape: btape.c:1055-0 Test with zero data, should give the maximum throughput.
btape: btape.c:904-0 Begin writing 3 files of 1.073 GB with raw blocks of 64512 bytes.
++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 2.182 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 4.511 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 1.835 MB/s
btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 2.449 MB/s

Это (и некоторые другие тесты) подтверждает скорость записи около 2 МБ / с, что неоправданно медленно. Почему это так? Что я могу сделать, чтобы повысить скорость записи до ожидаемой скорости (например, 100 МБ / с)?

редактировать

Похоже, что-то может быть не так с контроллером. После перезагрузки я смог некоторое время передавать данные с высокой скоростью, пока не возникло несколько ошибок PCI и скорость не снизилась до уровня сканирования:

ciss0: *** PCI-E LL correctable errors, count=10546, LLErrStatus=0x80000004
ciss0: *** PCI-E LL correctable errors, count=20570, LLErrStatus=0x80000004
ciss0: *** PCI-E LL correctable errors, count=30995, LLErrStatus=0x80000004
ciss0: *** PCI-E LL correctable errors, count=41101, LLErrStatus=0x80000004
ciss0: *** PCI-E LL correctable errors, count=51400, LLErrStatus=0x80000004
ciss0: *** PCI-E LL correctable errors, count=61729, LLErrStatus=0x80000004

Возможно, карта неправильно установлена или что-то в этом роде.

Answer 1

Я поменял местами контроллер SAS HP SmartArray P400 на контроллер SAS LSI 3041E. Это решило мои проблемы с производительностью, теперь я могу комфортно создавать резервные копии на высокой скорости (на практике я могу достигать около 70 МБ / с). Ниже вы можете найти результаты того же теста производительности, который использовался ранее:

$ btape /dev/nsa0
Tape block granularity is 1024 bytes.
btape: butil.c:291-0 Using device: "/dev/nsa0" for writing.
btape: btape.c:471-0 open device "LTO-4" (/dev/nsa0): OK
*rewind
btape: btape.c:576-0 Rewound "LTO-4" (/dev/nsa0)
*speed
btape: btape.c:1055-0 Test with zero data, should give the maximum throughput.
btape: btape.c:904-0 Begin writing 3 files of 1.073 GB with raw blocks of 64512 bytes.
++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 71.58 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 119.3 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 134.2 MB/s
btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 100.6 MB/s

btape: btape.c:904-0 Begin writing 3 files of 2.147 GB with raw blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 143.1 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 153.3 MB/s
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 143.1 MB/s
btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 146.4 MB/s

btape: btape.c:904-0 Begin writing 3 files of 4.294 GB with raw blocks of 64512 bytes.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 165.1 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 165.1 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 165.1 MB/s
btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 165.1 MB/s

btape: btape.c:1067-0 Test with random data, should give the minimum throughput.
btape: btape.c:904-0 Begin writing 3 files of 1.073 GB with raw blocks of 64512 bytes.
++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 53.69 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 51.13 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 53.69 MB/s
btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 52.80 MB/s

btape: btape.c:904-0 Begin writing 3 files of 2.147 GB with raw blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 59.65 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 58.04 MB/s
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 58.04 MB/s
btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 58.56 MB/s

btape: btape.c:904-0 Begin writing 3 files of 4.294 GB with raw blocks of 64512 bytes.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 60.49 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 70.41 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 69.27 MB/s
btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 66.41 MB/s

btape: btape.c:1081-0 Test with zero data and bacula block structure.
btape: btape.c:959-0 Begin writing 3 files of 1.073 GB with blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 71.58 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 76.70 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 71.58 MB/s
btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 73.21 MB/s

btape: btape.c:959-0 Begin writing 3 files of 2.147 GB with blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 93.37 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 85.90 MB/s
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 89.48 MB/s
btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 89.48 MB/s

btape: btape.c:959-0 Begin writing 3 files of 4.294 GB with blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 97.61 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 99.88 MB/s
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 97.61 MB/s
btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 98.35 MB/s

btape: btape.c:1093-0 Test with random data, should give the minimum throughput.
btape: btape.c:959-0 Begin writing 3 files of 1.073 GB with blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 41.30 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 39.77 MB/s
+++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 41.30 MB/s
btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 40.77 MB/s

btape: btape.c:959-0 Begin writing 3 files of 2.147 GB with blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 45.69 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 44.74 MB/s
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 44.74 MB/s
btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 45.05 MB/s

btape: btape.c:959-0 Begin writing 3 files of 4.294 GB with blocks of 64512 bytes.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 45.69 MB/s
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 49.94 MB/s
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
btape: btape.c:606-0 Wrote 1 EOF to "LTO-4" (/dev/nsa0)
btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 51.13 MB/s
btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 48.80 MB/s

*quit

Я почти уверен, что эта линия контроллера SAS не любит ленточные накопители в целом, о чем свидетельствуют следующие тесты, которые я выполнил:

• Я поменял SmartArray P400 на другой контроллер того же типа с одинаковыми результатами без PCI-E LL correctable errors .
• Я поменял кабель на другой, тот же результат.
• Я подключил жесткий диск к карте SmartArray P400, он работал без проблем.

Answer 2

Минимальная и максимальная скорости чтения и записи зависят от привода.
Максимальная несжатая скорость в 120 Мбит / с для LTO-4.
Стримеры Quantum LTO-4 HH имеют скорость передачи до 576 ГБ / ч. Предполагается сжатие 2: 1.
Реальная максимальная скорость этого привода составляет: 576 ГБ / ч / 2 = 288 * 1024 МБ / 3600 с = 81,92 МБ / с. Из спецификации привода:

Диапазон соответствия скорости передачи данных: от 33 до 80 МБ / с

Таким образом, вы никогда не получите 100 МБ / с

Редактировать:
Прочтите о тестировании накопителя на магнитной ленте с помощью Bacula.
Вам следует установить файл bacula-sd.conf и убедиться, что Bacula (демон Storage) не запущен или что вы отключили диск, который вы будете использовать для тестирования.