...
5GBというキャッシュに乗り切らないサイズのせいか、違いがぜんぜんわからん!
WTモード時とのデータの向上率の比較をしてみる
| 512 B; 100% Read; 0% random_QD1 | -44.2784 | 0 |
|---|---|---|
| 512 B; 100% Read; 0% random_QD32 | -2.24602 | 0 |
| 512 B; 50% Read; 0% random_QD1 | 103.7055 | 102.828 |
| 512 B; 50% Read; 0% random_QD32 | 181.8043 | 183.2034 |
| 512 B; 0% Read; 0% random_QD1 | 0 | 101.8742 |
| 512 B; 0% Read; 0% random_QD32 | 0 | -39.6489 |
| 4 KiB; 100% Read; 0% random_QD1 | -34.7772 | 0 |
| 4 KiB; 100% Read; 0% random_QD32 | -29.6001 | 0 |
| 4 KiB; 50% Read; 0% random_QD1 | -0.77824 | -1.62854 |
| 4 KiB; 50% Read; 0% random_QD32 | -9.38483 | -9.62174 |
| 4 KiB; 0% Read; 0% random_QD1 | 0 | 90.90597 |
| 4 KiB; 0% Read; 0% random_QD32 | 0 | -41.4706 |
| 256 KiB; 100% Read; 0% random_QD1 | -1.21428 | 0 |
| 256 KiB; 100% Read; 0% random_QD32 | 3.831043 | 0 |
| 256 KiB; 50% Read; 0% random_QD1 | 7.140573 | 8.666481 |
| 256 KiB; 50% Read; 0% random_QD32 | -21.9534 | -21.8982 |
| 256 KiB; 0% Read; 0% random_QD1 | 0 | 12.71637 |
| 256 KiB; 0% Read; 0% random_QD32 | 0 | -0.00466 |
| 1M-Seq-100%R_QD1 | 0.183323 | 0 |
| 1M-Seq-100%R_QD32 | 4.469601 | 0 |
| 1M-Seq-50%R_QD1 | -3.69594 | -5.69608 |
| 1M-Seq-50%R_QD32 | -7.78602 | -8.20952 |
| 1M-Seq-100%W_QD1 | 0 | -0.63321 |
| 1M-Seq-100%W_QD32 | 0 | 0.440793 |
| 1M-rand-100%R_QD1 | -7.9101 | 0 |
| 1M-rand-100%R_QD32 | -25.5283 | 0 |
| 1M-rand-50%R_QD1 | -10.3011 | -14.8897 |
| 1M-rand-50%R_QD32 | -18.1436 | -17.3741 |
| 1M-rand-100%W_QD1 | 0 | -7.48275 |
| 1M-rand-100%W_QD32 | 0 | -5.91396 |
0%でキャッシュ無し時と同じなので、512 B; 100% Read; 0% random_QD1の-44%というのは、キャッシュを有効にすると逆に性能劣化が起きてキャッシュ無しの半分の性能になっているパターンです。
...
4Disk-RAID0 WB
例によってWT/WBの対比が分からないので増分
| 512 B; 100% Read; 0% random_QD1 | -38.3926 | 0 |
|---|---|---|
| 512 B; 100% Read; 0% random_QD32 | -10.4696 | 0 |
| 512 B; 50% Read; 0% random_QD1 | 105.3036 | 105.2979 |
| 512 B; 50% Read; 0% random_QD32 | 182.4146 | 183.829 |
| 512 B; 0% Read; 0% random_QD1 | 0 | 100.2315 |
| 512 B; 0% Read; 0% random_QD32 | 0 | -31.7521 |
| 4 KiB; 100% Read; 0% random_QD1 | -15.3525 | 0 |
| 4 KiB; 100% Read; 0% random_QD32 | -9.96226 | 0 |
| 4 KiB; 50% Read; 0% random_QD1 | 4.451638 | 3.060278 |
| 4 KiB; 50% Read; 0% random_QD32 | -5.8848 | -5.67845 |
| 4 KiB; 0% Read; 0% random_QD1 | 0 | 78.77088 |
| 4 KiB; 0% Read; 0% random_QD32 | 0 | -44.7767 |
| 256 KiB; 100% Read; 0% random_QD1 | -13.1805 | 0 |
| 256 KiB; 100% Read; 0% random_QD32 | 1.193501 | 0 |
| 256 KiB; 50% Read; 0% random_QD1 | 17.66127 | 15.54095 |
| 256 KiB; 50% Read; 0% random_QD32 | 0.809517 | 2.130234 |
| 256 KiB; 0% Read; 0% random_QD1 | 0 | -7.04535 |
| 256 KiB; 0% Read; 0% random_QD32 | 0 | -18.4334 |
| 1M-Seq-100%R_QD1 | -2.46664 | 0 |
| 1M-Seq-100%R_QD32 | 2.463172 | 0 |
| 1M-Seq-50%R_QD1 | -3.53151 | -4.23811 |
| 1M-Seq-50%R_QD32 | -2.97517 | -3.60646 |
| 1M-Seq-100%W_QD1 | 0 | -20.8247 |
| 1M-Seq-100%W_QD32 | 0 | -12.7551 |
| 1M-rand-100%R_QD1 | -1.11088 | 0 |
| 1M-rand-100%R_QD32 | 4.778021 | 0 |
| 1M-rand-50%R_QD1 | -4.51558 | -6.17381 |
| 1M-rand-50%R_QD32 | 4.055717 | 3.391034 |
| 1M-rand-100%W_QD1 | 0 | -10.4651 |
| 1M-rand-100%W_QD32 | 0 | -13.909 |
CDMでも似た傾向がみれます。
4Disk-RAID5 WT
...
RAID0の時は512BQD32の書き込みが66kIOPSあったのに対して、RAID5の時は26kIOPSまで落ちたので、やはりパリティー計算が必要なRAIDのオーバーヘッドは大きいです。
4Disk-RAID5 WB
| 512 B; 100% Read; 0% random_QD1 | -80.9008 | 0 |
|---|---|---|
| 512 B; 100% Read; 0% random_QD32 | -24.7416 | 0 |
| 512 B; 50% Read; 0% random_QD1 | 0.374355 | 0.015933 |
| 512 B; 50% Read; 0% random_QD32 | 67.39728 | 67.56659 |
| 512 B; 0% Read; 0% random_QD1 | 0 | 482.0557 |
| 512 B; 0% Read; 0% random_QD32 | 0 | 66.55948 |
| 4 KiB; 100% Read; 0% random_QD1 | -77.3743 | 0 |
| 4 KiB; 100% Read; 0% random_QD32 | -10.1411 | 0 |
| 4 KiB; 50% Read; 0% random_QD1 | -7.2077 | -5.82038 |
| 4 KiB; 50% Read; 0% random_QD32 | 46.44116 | 46.29059 |
| 4 KiB; 0% Read; 0% random_QD1 | 0 | 479.8198 |
| 4 KiB; 0% Read; 0% random_QD32 | 0 | 98.44912 |
| 256 KiB; 100% Read; 0% random_QD1 | 11.12418 | 0 |
| 256 KiB; 100% Read; 0% random_QD32 | 6.039454 | 0 |
| 256 KiB; 50% Read; 0% random_QD1 | 59.67971 | 61.75022 |
| 256 KiB; 50% Read; 0% random_QD32 | 8.059076 | 7.317294 |
| 256 KiB; 0% Read; 0% random_QD1 | 0 | 159.8849 |
| 256 KiB; 0% Read; 0% random_QD32 | 0 | 130.9874 |
| 1M-Seq-100%R_QD1 | 3.951161 | 0 |
| 1M-Seq-100%R_QD32 | 5.272636 | 0 |
| 1M-Seq-50%R_QD1 | 60.79148 | 61.17785 |
| 1M-Seq-50%R_QD32 | 14.32811 | 16.1741 |
| 1M-Seq-100%W_QD1 | 0 | 174.7787 |
| 1M-Seq-100%W_QD32 | 0 | 94.76335 |
| 1M-rand-100%R_QD1 | 1.722071 | 0 |
| 1M-rand-100%R_QD32 | 8.186769 | 0 |
| 1M-rand-50%R_QD1 | 57.84206 | 61.04148 |
| 1M-rand-50%R_QD32 | 16.93755 | 16.22543 |
| 1M-rand-100%W_QD1 | 0 | 147.958 |
| 1M-rand-100%W_QD32 | 0 | 19.62272 |
通説通り、RAID5の時はWBキャッシュがあると性能向上があります。512BQD32の書き込みがWT時には26kIOPSでしたがWB時には44kIOPSまで上がりました。
...
4000円前後で買える割にはそこまで悪くないと思います。RAID5で運用する際にはBBU+キャッシュを、0で運用する際にはキャッシュしない設定にする、と言うのがベストのようです。
設定手順
| 目次 | ||
|---|---|---|
|
| 情報 |
|---|
| 実はCDMだけで良かったのでは |
Related articles
| ラベル別コンテンツ | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ページ プロパティ | ||
|---|---|---|
| ||
|