SanDisk SSD Plusシリーズは2TBの方が480GBより遅く見えちゃう
前回、SanDisk SDSSDA-2T00-G26がREGZAの2番組同時録画と別番組再生に追いつけなかった話で興味が出たので、同じシリーズの480GB(SDSSDA-480G-J26)も持ってたので同じ条件で軽く計測してみた。古いSSD同士で何をいまさらって感じがあるけど、まあ見てみたかったので。
これを見ると480GBの方がガタガタではあるけれども、予測しやすい理屈に合った動きをしているように見えるし、平均書き込み速度で上回ってて、レイテンシーの面でも優秀。SSDは容量が大きい方がだいたい書き込み速度が上がる印象だけどこういうこともあるんだなと。ファームウェアのリビジョンによる違いなのかもしれないけど。
と思ったら普通にデータシートに1TBの方が他より遅いって書いてあった。2TBは最速っぽく書いてあるけど。
- Read/write speeds of up to 545MB/s/450MBs** [2TB]
- Read/write speeds of up to 535MB/s/350MBs** [1TB]
- Read/write speeds of up to 535MB/s/445MBs** [480GB]
- Read/write speeds of up to 530MB/s/440MBs** [240GB]
ちなみに実際のTBWはどちらも使いすぎってわけではなくて、大した値ではなかった。
[480GB]
$ sudo smartctl -A /dev/disk/by-id/ata-SanDisk_SDSSDA480G_XYZ -d sat
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-6.1.0-1009-oem] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
5 Retired_Block_Count 0x0032 100 100 000 Old_age Always - 0
9 Power_On_Hours_and_Msec 0x0032 000 100 000 Old_age Always - 11604h+00m+00.000s
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 1926
165 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 7241469593843
166 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 2
167 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 0
168 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 15
169 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 0
170 Reserve_Block_Count 0x0032 100 100 000 Old_age Always - 0
171 Program_Fail_Count 0x0032 100 100 000 Old_age Always - 0
172 Erase_Fail_Count 0x0032 100 100 000 Old_age Always - 0
173 Unknown_SandForce_Attr 0x0032 100 100 000 Old_age Always - 8
174 Unexpect_Power_Loss_Ct 0x0032 100 100 000 Old_age Always - 120
187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0
188 Command_Timeout 0x0032 100 100 000 Old_age Always - 0
194 Temperature_Celsius 0x0022 061 022 000 Old_age Always - 39 (Min/Max 0/78)
199 SATA_CRC_Error_Count 0x0032 100 100 000 Old_age Always - 0
230 Life_Curve_Status 0x0032 100 100 000 Old_age Always - 3277067780859
232 Available_Reservd_Space 0x0033 100 100 004 Pre-fail Always - 100
233 SandForce_Internal 0x0032 100 100 000 Old_age Always - 3950
234 SandForce_Internal 0x0032 100 100 000 Old_age Always - 43857
241 Lifetime_Writes_GiB 0x0030 253 253 000 Old_age Offline - 13081
242 Lifetime_Reads_GiB 0x0030 253 253 000 Old_age Offline - 6245
244 Unknown_Attribute 0x0032 000 100 000 Old_age Always - 0
-> TBW: ~13 TB
[2TB]
$ sudo smartctl -A /dev/disk/by-id/ata-SanDisk_SSD_PLUS_2000GB_XYZ -d sat
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-6.1.0-1009-oem] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
5 Reallocated_Sector_Ct 0x0032 100 100 000 Old_age Always - 0
9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 11767
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 343
165 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 1378
166 Unknown_Attribute 0x0032 100 100 --- Old_age Always - 10
167 Unknown_Attribute 0x0032 100 100 --- Old_age Always - 98
168 Unknown_Attribute 0x0032 100 100 --- Old_age Always - 27
169 Unknown_Attribute 0x0032 100 100 --- Old_age Always - 1623
170 Unknown_Attribute 0x0032 100 100 --- Old_age Always - 0
171 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 0
172 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 0
173 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 10
174 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 239
184 End-to-End_Error 0x0032 100 100 --- Old_age Always - 0
187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0
188 Command_Timeout 0x0032 100 100 --- Old_age Always - 0
194 Temperature_Celsius 0x0022 058 071 000 Old_age Always - 42 (Min/Max 14/71)
199 UDMA_CRC_Error_Count 0x0032 100 100 --- Old_age Always - 0
230 Unknown_SSD_Attribute 0x0032 100 100 000 Old_age Always - 3698000397149
232 Available_Reservd_Space 0x0033 100 100 005 Pre-fail Always - 100
233 Media_Wearout_Indicator 0x0032 100 100 --- Old_age Always - 21640
234 Unknown_Attribute 0x0032 100 100 000 Old_age Always - 37214
241 Total_LBAs_Written 0x0030 100 100 000 Old_age Offline - 14543
242 Total_LBAs_Read 0x0030 100 100 000 Old_age Offline - 9730
244 Unknown_Attribute 0x0032 000 100 --- Old_age Always - 0
-> TBW: ~14.5 TB