> ## Documentation Index > Fetch the complete documentation index at: https://planetscale.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Per-shard sizing > Adjust VTTablet sizes for individual shards in a Vitess keyspace export const PlatformAvailability = ({current, vitess, postgres, neki}) => { const docsHref = path => { if (!path) return path; const normalized = path.startsWith('/') ? path : `/${path}`; return normalized; }; const labels = { vitess: 'Vitess', postgres: 'Postgres', neki: 'Neki' }; const combinedLabels = { both: 'Vitess and Postgres', all: 'Vitess, Neki, and Postgres', 'postgres-neki': 'Postgres and Neki' }; if (combinedLabels[current]) { return

{combinedLabels[current]}

; } const hasVitess = current === 'vitess' || Boolean(vitess); const hasPostgres = current === 'postgres' || Boolean(postgres); const hasNeki = current === 'neki' || Boolean(neki); const only = [hasVitess, hasPostgres, hasNeki].filter(Boolean).length === 1; const engines = []; if (current === 'vitess' || current === 'postgres' || current === 'neki') engines.push(current); if (hasVitess && current !== 'vitess') engines.push('vitess'); if (hasNeki && current !== 'neki') engines.push('neki'); if (hasPostgres && current !== 'postgres') engines.push('postgres'); return

{engines.map(engine => { const isCurrent = current === engine; const href = docsHref(engine === 'vitess' ? vitess : engine === 'postgres' ? postgres : neki); const label = only ? `${labels[engine]} only` : labels[engine]; const state = isCurrent || !href ? 'current' : 'link'; if (isCurrent || !href) { return {label} ; } return {label} ; })}

; }; Per-shard sizing lets you adjust the VTTablet size of individual shards in a sharded Vitess keyspace instead of resizing the whole keyspace. A shard that takes more traffic can run more CPU and memory than the rest of the keyspace, and on [Metal](/docs/plans/planetscale-skus#metal) it can run more local storage. Enable per-shard sizing from the keyspace Shards tab, then set a size on any shard. Shards you don't set keep the keyspace default. ## Eligibility Per-shard sizing is available on a Vitess keyspace that: * Has two or more shards, all covering equal [key ranges](/docs/vitess/sharding/vindexes). A four-shard keyspace named `-40`, `40-80`, `80-c0`, `c0-` is eligible. One named `-80`, `80-c0`, `c0-`, where the first shard covers half the keyspace and the others cover a quarter each, is not. * Is not imported or external If **Enable per-shard sizing** is not shown on the Shards tab, the keyspace is not eligible. You cannot enable per-shard sizing while a [keyspace resize](/docs/vitess/cluster-configuration#adjust-your-cluster-size) or [deploy request](/docs/vitess/schema-changes/deploy-requests) is in progress. ## Enable per-shard sizing Enabling per-shard sizing is metadata only. Existing key ranges, [VSchema](/docs/vitess/sharding/vschema), routing, and the keyspace default cluster size stay the same until you resize a shard. In the [PlanetScale dashboard](https://app.planetscale.com), open the Vitess database and select the branch. Open the keyspace and go to the **Shards** tab. Click **Enable per-shard sizing**. The dialog confirms the shard count and default size, for example: "This keyspace has N shards with a default size of PS-X. Once enabled you will be able to adjust the sizes of individual shards." Confirm. You can then set sizes on individual shards, or leave shards on the keyspace default. ## Resize a shard After per-shard sizing is enabled, resize a shard the same way you [resize a keyspace](/docs/vitess/cluster-configuration#adjust-your-cluster-size): pick a cluster size and save. This changes the CPU, memory, and, on Metal, the local storage for that shard's primary and replicas. Clearing a shard's size returns it to the keyspace default. All shards in a keyspace must stay on the same storage class: all [Metal](/docs/plans/planetscale-skus#metal) or all [network-attached storage](/docs/plans/planetscale-skus#network-attached-storage). The size picker only lists sizes that match the keyspace storage class. ## Need help? Get help from [the PlanetScale Support team](https://planetscale.com/contact?initial=support), or join our [Discord community](https://pscale.link/community) to see how others are using PlanetScale.