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Показаны сообщения с ярлыком SSD. Показать все сообщения
Показаны сообщения с ярлыком SSD. Показать все сообщения

четверг, 19 мая 2011 г.

RHEL 6 + software RAID из SSD дисков

Такая связка крайне не рекомендуется. Так как программный RAID в Linux не поддерживает команду TRIM. Если же RAID требуется, то, например, для замены RAID-1 (зеркало) можно использовать LVM mirror, так как он поддерживает команду TRIM.

In addition, keep in mind that MD (software raid) does not support discards. In contrast, the logical volume manager (LVM) and the device-mapper (DM) targets that LVM uses do support discards. The only DM targets that do not support discards are dm-snapshot, dm-crypt, and dm-raid45. Discard support for the dm-mirror was added in Red Hat Enterprise Linux 6.1.
Red Hat also warns that software RAID levels 1, 4, 5, and 6 are not recommended for use on SSDs. During the initialization stage of these RAID levels, some RAID management utilities (such as mdadm) write to all of the blocks on the storage device to ensure that checksums operate properly. This will cause the performance of the SSD to degrade quickly.

Источник: RHEL 6 Storage Guide

Какая файловая система наиболее предпочтительна для SSD дисков?

ext4, потому что поддерживает команду TRIM (опция монтирования discard).

At present, ext4 is the only fully-supported file system that supports discard. To enable discard commands on a device, use the mount option discard. For example, to mount /dev/sda2 to /mnt with discard enabled, run:
mount -t ext4 -o discard /dev/sda2 /mnt
By default, ext4 does not issue the discard command. This is mostly to avoid problems on devices which may not properly implement the discard command. The Linux swap code will issue discard commands to discard-enabled devices, and there is no option to control this behavior.

(с) RHEL 6 Storage Guide

Какой интерфейс для подключения SSD предпочтителен?

PCI-Express!

The first class of SSDs use a PCI-Express connection, which offers the fastest I/O throughput compared to other classes. This class also has a very low latency for random access.

(с) RHEL 6 Storage Guide

понедельник, 25 октября 2010 г.

SSD накопитель Corsair Force Series F120

Поступила в распоряжение вот такая вот железка: Corsair Force Series F120. Одной из ключевых его фич является поддержка нового контроллера: SandForce SF-1200 SSD Processor.

Вот хорошие обзоры:
http://www.storagereview.com/corsair_force_f120_ssd_review

воскресенье, 9 мая 2010 г.

SMART мониторинг SuperTalent UltraDrive GX

Если пытаться вызывать команду smartctl --all /dev/sda в Debian Lenny на SSD диск SuperTalent UltraDrive, то в ответ мы получим кучу бреда. Это объясняется тем, что версия smartmontools старовата в Дебе и надо собрать smartmontools из svn: http://phpsuxx.blogspot.com/2010/02/smartmontools-5391.html и после этого будет стройная картинка:


smartctl 5.40 2010-05-04 r3103 [x86_64-unknown-linux-gnu] (local build)
Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF INFORMATION SECTION ===
Model Family: SuperTalent UltraDrive GX SSD
Device Model: STT_FTM28GX25H
Serial Number: P601148-AFBX-C089053
Firmware Version: 1819
User Capacity: 128,035,676,160 bytes
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Sun May 9 23:20:34 2010 MSD
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status: (0x00) Offline data collection activity
was never started.
Auto Offline Data Collection: Disabled.
Self-test execution status: ( 0) The previous self-test routine completed
without error or no self-test has ever
been run.
Total time to complete Offline
data collection: ( 0) seconds.
Offline data collection
capabilities: (0x1d) SMART execute Offline immediate.
No Auto Offline data collection support.
Abort Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
No Conveyance Self-test supported.
No Selective Self-test supported.
SMART capabilities: (0x0003) Saves SMART data before entering
power-saving mode.
Supports SMART auto save timer.
Error logging capability: (0x00) Error logging NOT supported.
General Purpose Logging supported.
Short self-test routine
recommended polling time: ( 0) minutes.
Extended self-test routine
recommended polling time: ( 0) minutes.

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x0000 --- --- --- Old_age Offline - 6
9 Power_On_Hours 0x0000 --- --- --- Old_age Offline - 2281
12 Power_Cycle_Count 0x0000 --- --- --- Old_age Offline - 0
184 Initial_Bad_Block_Count 0x0000 --- --- --- Old_age Offline - 20
195 Program_Failure_Blk_Ct 0x0000 --- --- --- Old_age Offline - 0
196 Erase_Failure_Blk_Ct 0x0000 --- --- --- Old_age Offline - 0
197 Read_Failure_Blk_Ct 0x0000 --- --- --- Old_age Offline - 0
198 Read_Sectors_Tot_Ct 0x0000 --- --- --- Old_age Offline - 606564133
199 Write_Sectors_Tot_Ct 0x0000 --- --- --- Old_age Offline - 313738725
200 Read_Commands_Tot_Ct 0x0000 --- --- --- Old_age Offline - 14241593
201 Write_Commands_Tot_Ct 0x0000 --- --- --- Old_age Offline - 19250806
202 Error_Bits_Flash_Tot_Ct 0x0000 --- --- --- Old_age Offline - 642388
203 Corr_Read_Errors_Tot_Ct 0x0000 --- --- --- Old_age Offline - 621881
204 Bad_Block_Full_Flag 0x0000 --- --- --- Old_age Offline - 0
205 Max_PE_Count_Spec 0x0000 --- --- --- Old_age Offline - 10000
206 Min_Erase_Count 0x0000 --- --- --- Old_age Offline - 1
207 Max_Erase_Count 0x0000 --- --- --- Old_age Offline - 8407
208 Average_Erase_Count 0x0000 --- --- --- Old_age Offline - 242
209 Remaining_Lifetime_Perc 0x0000 --- --- --- Old_age Offline - 98
211 Unknown_Attribute 0x0000 --- --- --- Old_age Offline - 0
212 Unknown_Attribute 0x0000 --- --- --- Old_age Offline - 0
213 Unknown_Attribute 0x0000 --- --- --- Old_age Offline - 0


Очень радует параметр: Remaining_Lifetime_Perc, очень интеллектуально :)

вторник, 2 февраля 2010 г.

О линейных скоростях SSD

Вот как-то так:
dd if=/dev/sdc of=/dev/null
250069680+0 records in
250069680+0 records out
128035676160 bytes (128 GB) copied, 1239.9 s, 103 MB/s


Модельку SSD выложу чуть позже.

понедельник, 1 февраля 2010 г.

Тестирование скорости рандомного доступа к диску

Линейную скорость чтения так или иначе можно смерить. Вот со случайным доступом значительно сложнее, но тут на помощь нам приходит отличная тулза: http://www.linuxinsight.com/how_fast_is_your_disk.html. Скачать ее можно тут и тут.


cd /usr/src
mkdir -p seeker
cd seeker
wget http://fastvps.googlecode.com/svn/trunk/other/seeker.c
gcc seeker.c -o seeker


Запуск теста производится так:

./seeker /dev/sda


Примеры результатов для моего железа.

SATA без RAID:

Results: 62 seeks/second, 15.90 ms random access time
Results: 62 seeks/second, 15.97 ms random access time
Results: 62 seeks/second, 16.04 ms random access time


SATA в soft-raid 1

Results: 65 seeks/second, 15.21 ms random access time
Results: 63 seeks/second, 15.81 ms random access time
Results: 65 seeks/second, 15.25 ms random access time


Один SSD накопитель
Results: 6547 seeks/second, 0.15 ms random access time
Results: 6694 seeks/second, 0.15 ms random access time
Results: 6594 seeks/second, 0.15 ms random access time

4xSAS 15000 Cheetah в RAID-10
Results: 200 seeks/second, 4.98 ms random access time
Results: 198 seeks/second, 5.03 ms random access time
Results: 202 seeks/second, 4.94 ms random access time


Ну что же, в этой весовой категории (seek rate) SSD выходит безоговорочным победителем.